Ge Matrix Research Articles

Research on extreme weather insurance and real estate decision model based on AHP-EWM-CVM and K-Means clustering technology

Aiming at the challenge of extreme weather to insurance industries and real estate industries, this paper constructs an insurance model and a real estate decision model. The insurance model uses analytic hierarchy Process (AHP), entropy weight method (EWM), coefficient of variation method (CVM) and K-Means clustering algorithm to evaluate the risk level in different regions and predict the values of risk indicators up to the year 2035, and then calculate future insurance premiums. At the same time, multiple constraints are used to determine the future risk safety interval, which provides the basis for insurance companies to make decisions. In the case application, this paper finds that China is currently medium risk region and will be a medium risk region in the future, and obtains the time point when insurance companies can underwrite policies in this region. In addition, this paper also constructs a real estate decision model, which comprehensively considers three factors: risk, development potential and risk cost, and provides decision making basis for real estate developers through GE matrix. In the case application, this paper predicts that in the next nearly ten years, China is a medium willingness and medium risk area, suggesting that real estate developers should be cautious in deciding whether to develop. This study provides decision support for insurance industries and real estate industries to deal with extreme weather, which is of theoretical and practical significance.

Low-temperature growth of narrow optical gap highly conducting nc-Ge thin films with superior crystallinity involving dominant orientation

The nc-Ge thin films are grown at a moderately low temperature (∼220 °C) in rf PECVD via optimizing the GeH4 plasma with H2-dilution, within 97.5 ≤ D(H2)(%) ≤ 99.5. At elevated D(H2), while the bonded H-content in the matrix reduces, the film's crystallinity and dc conductivity increase. However, the optical band gap widens for 97.5 ≤ D(H2)(%) ≤ 98.5, via the elevated quantum confinement effect from the increased number of Ge-ncs of dimension below Bohr radius. Conversely, for D(H2) ≥ 98.5%, switching in the quantum effect in larger-sized Ge-ncs induces the band gap narrowing. Significantly reduced ultra-nanocrystalline-Ge (unc-Ge) component occupying the grain boundary zone, minimizes the contribution of grain-boundary defects. However, the persistent amorphous Ge matrix becomes highly defective and less dense, and those induce enhanced O-absorption from the ambient in the dominant Ge-Ox (x < 2) configuration. On increased crystallinity, the activation energies of dipole relaxation (ΔEτ) and resistance (ΔE) in the impedance data reduce dominantly in the a-Ge component than its nc-Ge counterpart, which occurs identically for the dc conductivity when the amorphous component in the matrix sharply disappears at increased D(H2) > 98.5%. A narrow band gap (∼0.90 eV), conducting (σd ∼3.0 ×10−2 S cm−1), and photosensitive nc-Ge network, involving dominant <111>-oriented Ge-ncs (∼35.2 nm) of enriched volume fraction (XC ∼90.2%), obtained at D(H2) ∼99.5%, seems extremely useful for need-based applications as a narrow band gap absorber layer in the bottom sub-cell of flexible high-efficiency cost-effective multijunction thin film solar cells.

Molecular beam epitaxy growth of superconducting tantalum germanide

Developing alternative material platforms for use in superconductor–semiconductor hybrid structures is desirable due to limitations caused by intrinsic microwave losses present in commonly used III/V material systems. With the recent reports on tantalum superconducting qubits that show improvements over the Nb and Al counterparts, exploring Ta the superconductor in hybrid material systems is promising. Here, we study the growth of Ta on semiconducting Ge (001) substrates grown via molecular beam epitaxy. We show that at a growth temperature of 400 °C, the Ta diffuses into the Ge matrix in a self-limiting nature resulting in smooth and abrupt surfaces and interfaces with roughness on the order of 3–7 Å as measured by atomic force microscopy and x-ray reflectivity. The films are found to be a mixture of Ta5Ge3 and TaGe2 binary alloys and form a native oxide that seems to form a sharp interface with the underlying film. These films are superconducting with a TC∼1.8−2 K and HC⊥∼1.88 T, HC∥∼5.1 T. These results show this tantalum germanide film to be promising for future superconducting quantum information platforms.

Enhancing Organizational Culture and Productivity through Innovative Performance Appraisal: A Design Science Research Approach

Performance Appraisal is crucial for Human Resource Management (HRM) to determine compensation, enhance performance and develop competencies. Regular and comprehensive appraisals enable companies to devise effective strategies, boost productivity, and gain competitive advantage. The research aims to develop Performance Appraisal artifacts using Balanced Scorecard (BSC), 360°Feedback, and GE McKinsey 9 Box Matrix (GE Matrix), using Design Science (DS) research approach. This represents a novel contribution to the research. The implementation of the Design Science Research Method (DSRM) is described, emphasizing its focus on innovative information system designs to address practical organizational challenges. This study can be used as an additional reference for DS research on HRM.

Strategi Pengembangan Usaha Mikro Kecil Menengah (UMKM) Kerupuk Sagu Di Desa Pulau Banjar Kari,Kecamatan Kuantan Tengah, Kabupaten Kuantan Singingi

Sago cracker MSMEs still produce sago to the extent of the household industry, simple processing technology and lack of promotion of sago crackers. The research objective was to analyze the internal and external environment of sago cracker MSMEs, formulate and determine technical strategies and policies for the development of sugo cracker MSMEs in Kuanta Singingi Regency. This research was conducted by survey with quantitative and qualitative descriptive analysis. Qualitative descriptive using IFE and EFE matrix while qualitative descriptive wing SWOT method. The total internal factor evaluation (IFE) score was 2.6694 and the total external factor evaluation (EFE) score was 2.9857. The GE matrix results in sago cracker MSMEs located in quadrant (hold and maintain), namely market and product development. The resulting strategies for the development of sago cracker MSMEs are a MSMEs have a long-term development strategy by The experience of MSM owners has been on busmess for a long time, c) Policy and political support for the development of MSMEX d) MSMEs get guidance from the government, dy Participate in exhibitions and expus organized by the government both inside and outside the area. e) Product diversification and innovation by utilizing trend models in the community Marketing strategies to communities, inibes religions and other segments of society. ) Carrying out product mapping so that the product innovations produced cannot be imitated, h) Product penetration marketing strategies through discounts and price reductions, i) Digitalization strategy for marketing MSME products to reach a wider market. Develop partnerships between business actors in product and market development andk) Establishing partnerships with raw material suppliers

Improving properties of Litsea cubeba oil Pickering emulsion-loaded gelatin-based bio-nanocomposite film via optimizing blending ratio: Application for mango preservation

To improve the biological and water-barrier properties of gelatin film, we incorporated the red roselle extract (RRE), ZnO nanoparticles (ZnO), and Litsea cubeba oil Pickering emulsion (LCON) into the GE film. The effect of RRE, ZnO, and LOCN on the properties of GE film was assessed using Box–Behnken response surface design (BBD). The BBD results revealed that these compounds greatly affect the properties of the film, especially the contribution of ZnO/LCON on the mechanical and water barrier properties of the film. The optimal antifungal (80.15%), antibacterial (31.24 mm), antioxidant (73.00%), tensile strength (42.03 MPa), elongation at break (25.50%), water vapor permeability (18.01 g mm·m−2·Kpa−1·h−1), and water contact angle (110.2°) of the film were obtained at 1.10% RRE, 1.51% ZnO and 2.38% LCON. The X-ray diffraction pattern and FTIR spectra results indicated the change of molecular interactions and semi-crystalline structure in the film. The scanning electron microscopy, fluorescence image, and energy dispersive X-ray results revealed that the excellent dispersion of RRE, ZnO, and LCON in the GE matrix led to an even and smooth structure in the film. This structure offers a positive effect on improving the mechanical and barrier properties of the film. The colorful patterns were successfully printed on the film to provide essential product information. Due to its excellent biological, mechanical, and barrier properties, the optimized film was applied for mango preservation. The optimized GE/RRE/ZnO/LCON film significantly controlled the postharvest quality and anthracnose in mango. Thus, the GE/RRE/ZnO/LCON film has great potential for mango preservation in active packaging applications.

Light Pollution Impact Risk Measure Model Based on Ahp-Critic Method

With the intensification of light pollution, the assessment of light pollution risk level has become a focus topic. This paper proposes the LPIRM light pollution risk classification model to solve the problem of difficult accurate assessment of community light pollution risk degree. LPIRM model is divided into DRS and ELPI systems. Considering human and non-human factors, this paper selects 12 indicators to construct the District risk status system (DRS). The External light pollution impact index (ELPI) was constructed considering three main light pollution phenomena. In this paper, AHP-CRITIC method is used to calculate the total value of DRS, and GE matrix is used to calculate the combined value of DRS and ELPI, so as to establish a Light pollution impact risk measure model (LPIRM) that comprehensively considers the internal stability of a community and the influence of external light. Finally, K-means algorithm was used to cluster the calculated results, and risk I-V light pollution risk classification was proposed. According to the classification results, the paper concluded that the risk classification based on LPIRM model has guiding significance for the proposal of subsequent light pollution solution strategies.

The Impact Factors and Management Policy of Digital Village Development: A Case Study of Gansu Province, China

(1) Background: Along with the maturity of smart cities, digital villages and smart villages are receiving more attention than ever before as the key to promote sustainable rural development. The Chinese government has made great efforts in promoting the digital development of villages in recent years, as evidenced by policies intensively introduced by the central and local governments, making China a typical representative country in the world. (2) Methods: This paper evaluates the performance and geographic pattern of rural digital development by the Geographic Information System (GIS) in Gansu, a less developed province in western China, and analyzes the driving mechanism of rural digital development using GeoDetector, providing a basis for spatial zoning and differentiated policy design for the construction, planning and management of digital villages based on the GE matrix. (3) Results: First, the development of digital villages shows a prominent geographical imbalance, with 79 counties divided into leader, follower and straggler levels. Second, digital villages show unsynchronized development in different dimensions, with the village facilities digitalization index in the lead and the village economy digitalization index lagging behind. Thirdly, the development of digital villages is characterized by significant spatial correlation and spillover effects, with cold and hot counties distributed in clusters, forming a “center-periphery” structure. Fourth, the factors show significant influence differentiation. They are classified into all-purpose, multifunctional and single-functional factors by their scope of action, and into key, important and auxiliary factors by their intensity of action. Fifth, the interaction and driving mechanism between different factors is quite complex, dominated by nonlinear enhancement and bifactor enhancement, and the synergistic effect of factor pairs helps increase the influence by 1–4 times. (4) Conclusions: It is suggested that the government develop differentiated policies for zoning planning and management based on the level of digital development of villages in combination with the factor influence and its driving mechanism and promote regional linkage and common development and governance through top-level design.

The epitaxial growth and unique morphology of InAs quantum dots embedded in a Ge matrix

In this work, we investigate the epitaxial growth of InAs quantum dots (QDs) on Ge substrates. By varying the growth parameters of growth temperature, deposition thickness and the growth rate of InAs, high density (1.2 × 1011 cm−2) self-assembled InAs QDs were successfully epitaxially grown on Ge substrates by solid-source molecular beam epitaxy and capped by Ge layers. Pyramid- and polyhedral-shaped InAs QDs embedded in Ge matrices were revealed, which are distinct from the lens- or truncated pyramid-shaped dots in InAs/GaAs or InAs/Si systems. Moreover, with a 200 nm Ge capping layer, one-third of the embedded QDs are found with elliptical and hexagonal nanovoids with sizes of 7–9 nm, which, to the best of our knowledge, is observed for the first time for InAs QDs embedded in a Ge matrix. These results provide a new possibility of integrating InAs QD devices on group-IV platforms for Si photonics.

Optimization of gold germanium (Au0.17Ge0.83) thin films for high sensitivity resistance thermometry

Gold–germanium (AuxGe1−x) solid solutions have been demonstrated as highly sensitive thin film thermometers for cryogenic applications. However, little is known regarding the performance of the films for thicknesses less than 100 nm. In response, we report on the resistivity and temperature coefficient of resistance (TCR) for sputtered films with thicknesses ranging from 10 to 100 nm and annealed at temperatures from 22 to 200 °C. The analysis is focused upon composition x=0.17, which demonstrates a strong temperature sensitivity over a broad range. The thinnest films are found to provide an enhancement in TCR, which approaches 20% K−1 at 10 K. Furthermore, reduced anneal temperatures are required to crystallize the Ge matrix and achieve a maximum TCR for films of reduced thickness. These features favor the application of ultra-thin films as high-sensitivity, on-device thermometers in micro- and nanolectromechanical systems.

Electronic and Magnetic Properties of Eutectoid Growth Mn-rich Ge1-xMnx Dilute Magnetic Semiconductors

Background: Dilute magnetic semiconductors (DMSs) have attracted great attention in recent years due to their potential applications in spintronic devices. Objective: This study aimed to investigate the magnetic and electronic properties of Mn-rich Ge semiconductors. Methods: The magnetic and electronic properties of eutectoid growth Mn-rich Ge1-xMnx dilute magnetic semiconductors (DMSs) with a high Mn dopant close to the composition of Ge2Mn are investigated by the first-principles calculations. Results: Using the diamond structure models of Ge24Mn8, Ge22Mn10, and Ge20Mn12, we show that the magnetic interactions of Mn atoms are dominated by ferrimagnetic coupling and that the Mn 3d states are substantially hybridized with the valence bands of the Ge matrix. Conclusion: This indicates that Mn-rich Ge1-xMnx DMSs demonstrate a ferromagnetic and metallic character, and their carriers can mobilize in the lattice more freely. The present investigation could provide insights into understanding the nature of transition-metal-rich dilute magnetic semiconductors.

Magnetic Ge:Mn nanocrystals grown by MBE on insulator substrate for solar cell and photodetector applications

In this work, we successfully grew novel dilute magnetic Ge:Mn nanocrystals (Ge:Mn NCs) on SiO2 thin film for metal-oxidesemiconductor (MOS) solar cell and photodetector applications. The innovative Ge:Mn NCs have been grown via solid-state dewetting of ultra-pure thin amorphous Ge:Mn nanolayer deposited by high precision molecular beam epitaxy (MBE) on thin SiO2/Si film. The morphological and structural properties of the Ge:Mn NCs have been determined by atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HR-TEM). The results indicate the formation of homogeneous Ge:Mn NCs on SiO2 with a well-defined spherical shape and small size (∼8 nm). The incorporation of Mn element into Ge matrix has been confirmed by scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX). The magnetic properties of the Ge:Mn NCs have been determined by the superconducting quantum interference device (SQUID). The results show that the Ge:Mn NCs are ferromagnetic and having a Curie temperature above room temperature (∼310 K). The electrical transport and the photocurrent generation in the novel Ge:Mn NCs embedded in the SiO2 film of MOS structure are studied by I-V and photocurrent spectroscopies. The results show that when the Ge:Mn NCs are inserted as an active layer in a SiO2 film of MOS structure, the photocurrent of the MOS structure increase 10 times higher than the dark current.The excellent structural, magnetic and optoelectric properties results indicate that the novel Ge:Mn NCs grown on insulator (SiO2) thin-film via solid-state dewetting can be integrated with spintronic and optoelectronic technologies to produce novel high-performance devices fully compatible with complementary oxide metal (CMOS) technology.

Unusual dislocation activity in Ge containing Sn particles

We report an unexpectedly high dislocation activity around Sn inclusions in the Ge matrix below the brittle-to-ductile (BDT) transition temperature of Ge as observed using transmission electron microscopy. These dislocations nucleate at the Sn/Ge interface in form of dislocation loops upon solidification of Sn inclusions on cooling. The Sn inclusions solidify ~130 °C below the BDT of Ge. The novel feature is the unusual extent of dislocation loops so far from the inclusions, especially since the mobility of dislocations is limited in Ge below BDT. Considering the velocity of dislocation in Ge below the BDT to be ≈10−11 ms−1, it is normally not enough to increase the loop size from ≈1 nm to more than 300 nm in the short solidification time. We propose that in addition to diffusive type heat propagation, the sudden energy release upon solidification of Sn in Ge matrix can also be carried away by the expanding dislocation loops, thereby enhancing the velocity of dislocations significantly below the BDT. The role of expanding dislocation loops at Sn/Ge interface upon solidification of inclusions is thus fundamentally significant in understanding the rapid dissipation of latent heat from nanocrystalline inclusions embedded in a matrix.

Nature of Photoelectric Effect in a Ge-on-Si SPAD at Ultralow Energy in Incident Pulsed Laser Radiation

The photoelectric effect in a Ge-on-Si single-photon avalanche detector (SPAD) at an ultralow energy in incident pulsed laser radiation is considered in the frame of the classical theory of the electrodynamics of continuous media. It is shown that the energy of incident laser radiation which is shared among a huge number of electrons in a Ge matrix can concentrate on only one of these through the effect of the constructive interference of the fields re-emitted by surrounding electrons. Conservation of energy in this case is upheld because of a substantial narrowing of the effective bandgap in heavily doped p-Ge, which is used in the design of the SPAD considered.

Microstructure and morphology of 2D arrays of Ge quantum dots in a Si/Al2O3 matrix

The paper presents the results of the microstructure and morphology study of two-dimensional Ge QD arrays in a Si/Al2O3 matrix formed by annealing multilayer periodic structures with Ge nanolayers in a Si/Al2O3 matrix. The distinctive features of samples in the series are the location and thickness of the Si barrier layers between Ge and aluminium oxide matrix. X-ray reflectometry and diffractometry and transmission electron microscopy studies have shown that large Al6Ge5 crystallites are formed and the multilayer structure is destroyed after annealing of the multilayer sample Al2O3/Ge without Si. It was found that the presence of Si barrier layers in multilayer Al2O3/Si/Ge structures reduces the interdiffusion of Al and Ge, but Ge1-xSix nanocrystallites are formed as a result of Si and Ge interdiffusion. Thus, the introduction of Si barrier layer into the Al2O3/Ge structure allowed obtaining of two-dimensional arrays of Ge1-xSix nanocrystallites with the penetration of Si up to 0.64.

Resistive Switching in Memristors Based on Ge/Si(001) Epitaxial Layers

The Ag/Ge/Si(001) stacks with threading dislocations growing through the Ge epitaxial layers (ELs) manifested bipolar resistive switching (RS) between two metastable resistance states. Scanning transmission electron microscopy (STEM) provided a direct evidenced the RS mechanism to consist in the electrodiffusion of Ag+ ions along the dislocations in the Ge ELs. Also, STEM revealed multiple RS cycling to result in the metallization of the Ge matrix around the dislocations and in the accumulation of Ag in the misfit dislocation layer near Ge/Si interface. Both above phenomena may lead potentially to degradation of the RS performance.

Sub-nm Near-Surface Activation Profiling for Highly Doped Si and Ge Using Differential Hall Effect Metrology (DHEM)

Contact resistivity at the metal-semiconductor interface is a strong function of the carrier concentration in the near surface. For next generation 2D/3D MOSFET transistors, industry has been investigating very highly doped materials (>1x1021cm-3) approaching alloy concentrations in Silicon and various Silicon-Germanium materials. All the while, contact development in Ge NMOS has favored co-doping approaches. Regardless of the material system, it is very important to accurately measure near-surface dopant activation. In this paper, we use Differential Hall Effect Metrology (DHEM) implemented on the ALPro™ tool to characterize the activation profiles in both materials. The method employs electrochemical means of reducing the electrically active thickness of a semiconductor film and determining the sheet resistance and mobility of the thinned down layer using Van der Pauw/Hall effect type measurements. By repeating this process and using differential equations, depth profiles of mobility and carrier concentration are obtained [1] at sub-nm resolutions.It is difficult to achieve high n-type dopant activation in Ge. Point defects in Ge are known to behave as acceptor sites and reduce the overall free electron density, particularly near the surface. Minimization of these defects is essential to achieving high performance Ge NMOS. Accurate analysis of dopant activation within 5 nm of the surface is critical to understanding effectiveness of various process steps on improving contact resistance. We have previously published a study on the effect of Ge co-doping with Sb and P on near-surface dopant activation. In Ge with only P-doping it was found that only ~5x1018cm-3 or 5% of the total surface dopants (~1x1020cm-3) were electrically active. With Sb as a co-dopant, the active electron concentration increased to ~2x1019cm-3 with a similar P chemical concentration. Prior work has shown similar increases in activation with co-doping but did not capture the significant decrease in electron concentration by 4x within 10 nm of the surface. Here, we further study the effects of the implantation and annealing processes on near-surface dopant activation in n-type Ge. Samples were prepared by growing 3 µm thick epi-Ge layers on Si substrates. Sample 1 was capped with 20 nm SiO2 and Sample 2 was capped with 20 nm Al2O3 to minimize implant damage and control implant depth. Both samples were implanted first with Sb (dose: 6x1014cm-2, energy: 65 keV) followed by P (dose: 6x1014cm-2, energy: 90 keV). Post-implant anneal was done at 500°C for 10 s in N2 to activate the dopants. ALProTM and SIMS measurements were done to characterize active dopant concentration and total chemical dopant concentration, respectively. The Al2O3 capped sample (Sample 2) showed significantly lower carrier concentration than the SiO2 capped sample (Sample 1) throughout the depth of the profile (Figure 1). Carrier concentration at the surface was lower by nearly an order of magnitude, decreasing from ~2x1019cm-3 to ~2x1018cm-3. Additionally, the peak concentration decreased from 1x1020cm-3 to 5x1019cm-3 at a depth of ~30 nm in both cases. The variations in the carrier profile for the Al2O3 capped sample also indicate greater process variation. SIMS profiles show that there is significant diffusion of Al into the Ge matrix after implant and anneal. Al chemical concentration is 1x1020cm-3 at the Ge surface and steadily decays up to a depth of more than 300 nm. This indicates that there is significant damage caused during the implantation process and the activation anneal is not enough to remove these defects. Al atoms then diffuse from the Al2O3 capping layer into the highly defective Ge substrate. Al is a p-type dopant in Ge and counter-dopes the Sb and P implants to reduce overall electron concentration in Sample 2. It is important to note the high resolution DHEM technique was able to resolve this important phenomenon right near the surface of the material.Additionally, we present early data on very highly phosphorus-doped (~1x1021cm-3) epitaxial silicon thin films grown on Si substrates. In very highly doped Silicon materials, the effect of near-alloy levels of dopant in the matrix on dopant deactivation is not well-known. Samples were obtained with different levels of dopant concentration above ~1x1021cm-3and different anneal temperatures. It was found that near-surface activation in these un-capped samples led to a lowering of activation in the <20nm region from the surface. Extensive post-DHEM metrology (using TEM and SIMS analysis) will also be presented demonstrating control and precision of DHEM data.

Magnetotransport Properties of Ferromagnetic Nanoparticles in a Semiconductor Matrix Studied by Precise Size-Selective Cluster Ion Beam Deposition.

The combination of magnetic and semiconducting properties in one material system has great potential for integration of emerging spintronics with conventional semiconductor technology. One standard route for the synthesis of magnetic semiconductors is doping of semiconductors with magnetic atoms. In many semiconductor–magnetic–dopant systems, the magnetic atoms form precipitates within the semiconducting matrix. An alternative and controlled way to realize such nanocomposite materials is the assembly by co-deposition of size-selected cluster ions and a semiconductor. Here we follow the latter approach to demonstrate that this fabrication route can be used to independently study the influence of cluster concentration and cluster size on magneto-transport properties. In this case we study Fe clusters composed of approximately 500 or 1000 atoms soft-landed into a thermally evaporated amorphous Ge matrix. The analysis of field and temperature dependent transport shows that tunneling processes affected by Coulomb blockade dominate at low temperatures. The nanocomposites show saturating tunneling magnetoresistance, additionally superimposed by at least one other effect not saturating upon the maximum applied field of 6 T. The nanocomposites’ resistivity and the observed tunneling magnetoresistance depend exponentially on the average distance between cluster surfaces. On the contrary, there is no notable influence of the cluster size on the tunneling magnetoresistance.

Growth and Magnetism of MnxGe1−x Heteroepitaxial Quantum Dots Grown on Si Wafer by Molecular Beam Epitaxy

Self-assembled MnGe quantum dots (QDs) were grown on Si (001) substrates using molecular beam epitaxy with different growth temperatures and Ge deposition thicknesses to explore the interaction among Mn doping, Ge deposition, the formation of intermetallics, and the ferromagnetism of QDs. With the introduction of Mn atoms, the QDs become large and the density significantly decreases due to the improvement in the surface migration ability of Ge atoms. The growth temperature is one of the most important factors deciding whether intermetallic phases form between Mn and Ge. We found that Mn atoms can segregate from the Ge matrix when the growth temperature exceeds 550 °C, and the strongest ferromagnetism of QDs occurs at a growth temperature of 450 °C. As the Ge deposition thickness increases, the morphology of QDs changes and the ferromagnetic properties decrease gradually. The results clearly indicate the morphological evolution of MnGe QDs and the formation conditions of intermetallics between Mn and Ge, such as Mn5Ge3 and Mn11Ge8.

(Invited) Differential Hall Effect Metrology (DHEM) Sub-Nm Profiling and Its Application to Dopant Activation in n-Type Ge

With silicon CMOS technology approaching its limits due to continued device scaling, many potential new channel materials have been proposed. Germanium shows considerable promise due to having higher electron and hole mobilities compared to silicon. In addition, the electron and hole mobilities are similar, making it a viable option for CMOS technology. High performance Ge PMOS has been demonstrated, but NMOS has lagged behind due to the difficulty in making low resistance contacts to n-type Ge. Contact resistance is a strong function of the carrier concentration at the semiconductor surface, and it is extremely difficult to achieve high electron activation in Ge. Point defects in Ge are known to behave as acceptor sites and reduce the overall electron activation, particularly near the surface. Minimization of these defects is essential to achieving high performance Ge NMOS. Techniques such as fluorine passivation and co-doping with Sb and P have been shown to reduce the defect density and improve dopant activation, but the impact of these methods in the near-surface regime has largely been uncharacterized. Accurate analysis of dopant activation within 5 nm of the surface is critical to understanding the effectiveness of such processes on improving contact resistance.Differential Hall Effect Metrology (DHEM) is a powerful method that provides dopant activation depth profiles at sub-nm resolution. The method employs electrochemical means of reducing the electrically active thickness of a semiconductor film and determining the sheet resistance and mobility of the thinned down layer using Van der Pauw/Hall effect type measurements. Repeating this process and using differential equations, depth profiles of mobility and carrier concentration are obtained [1].We have previously used the ALProTM tool employing the DHEM technique to study the effect of Ge co-doping with Sb and P on near-surface dopant activation [2]. In Ge with only P-doping, the active dopant concentration was ~5x1018cm-3 at the surface despite the P chemical concentration being ~1x1020cm-3, indicating that only 5% of the implanted dopants were electrically active. With co-doping of Sb and P, the active electron concentration increased to ~2x1019cm-3 with a similar P chemical concentration. Prior work has shown similar increases in activation with co-doping but did not capture the significant decrease in electron concentration by 4x within 10 nm of the surface. Here, we further study the effects of the implantation and annealing process on near-surface dopant activation in n-type Ge. Samples were prepared by growing 3 µm thick epi-Ge layers on Si substrates. Sample 1 was capped with 20 nm SiO2 and Sample 2 was capped with 20 nm Al2O3 to minimize implant damage and control implant depth. Both samples were implanted first with Sb (dose: 6x1014cm-2, energy: 65 keV) followed by P (dose: 6x1014cm-2, energy: 90 keV). Post-implant anneal was done at 500°C for 10 s in N2 to activate the dopants. ALProTM and SIMS measurements were done to characterize active dopant concentration and total chemical dopant concentration, respectively.The Al2O3 capped sample (Sample 2) showed significantly lower dopant activation than the SiO2 capped sample (Sample 1) throughout the depth of the profile (Figure 1). Active electron concentration at the surface was lower by nearly an order of magnitude, decreasing from ~2x1019cm-3 to ~2x1018cm-3. Additionally, the peak concentration decreased from 1x1020cm-3 to 5x1019cm-3 at a depth of ~30 nm in both cases. The variations in the carrier profile for the Al2O3 capped sample also indicate greater process variation. SIMS profiles show that there is significant diffusion of Al into the Ge matrix after implant and anneal. Al chemical concentration is 1x1020cm-3 at the Ge surface and steadily decays up to a depth of more than 300 nm. This indicates that there is significant damage caused during the implantation process and the activation anneal is not enough to remove these defects. Al atoms then diffuse from the Al2O3 capping layer into the highly defective Ge substrate. Al is a p-type dopant in Ge and effectively counter dopes the Sb and P implants to reduce overall electron concentration in the Al2O3 capped sample. It is important to note the high resolution DHEM technique was able to resolve this important phenomenon right near the surface of the material.