Application Of Germanium Research Articles

The mechanism of improving germanium metal–oxide–semiconductor field-effect transistors’ reliability by high-k dielectric and yttrium-doping: From the view of charge trapping

The application of germanium (Ge)-based transistors has long been restricted by the poor reliability of the gate dielectrics. One solution proposed in the experiment is capping the GeO2 layer with high-k dielectrics and further doping the dielectric with yttrium (Y) atoms. However, the strategy only works at a very small doping concentration window, and the underlying mechanism remains unclear. Here, we carry out first-principles calculations on a concrete Ge/GeO2/ZrO2 stack to study the structural and electronic properties of various defects before and after Y-doping and further calculate their exact charge-trapping rates by the Marcus charge transfer theory. We show that the Y atoms can effectively weaken the charge-trapping capability of vacancy defects in the ZrO2 layer, but on the other hand, they can induce some new types of active defects if the density is high. In addition, it is found that the Y atoms can have a very different effect even when doped to the same material. These results indicate that a precise control of the doping position and doping concentration is necessary to promote the reliability of Ge transistors.

The application of germanium(IV)-porphyrins as fluoride-selective ionophores for polymeric membrane electrodes

In this work, the possibility of using Ge(IV)-porphyrins as anion-selective ionophores for potentiometric measurements was tested. Conducted experiments shown that polymeric membranes doped with these compounds exhibit high selectivity towards fluoride anion. Ge(IV)-tetraphenylporphyrin was initially used as a ionophore, however rapid crystallization of this compound in the membrane phase was observed. To mitigate this problem, more lipophilic derivative with tert-butyl groups was synthesized and doped into polymeric membranes. Ge(IV)-porphyrins were shown to work according to charged carrier mechanism, requiring 10 to 20mol% of borate additive for optimal selectivity. The anti-Hofmeister selectivity pattern: F−>SCN−>ClO4−>Br−>NO3−>Cl− was observed for membranes containing Ge(IV)-porphyrin and anionic additive. Electrodes with these membranes responded to changes in fluoride concentration in fast and near-Nernstian fashion. Strong interaction between fluoride ion and tested ionophores resulted in the inversion of the F− calibration curve at high concentration, which was especially pronounced for electrodes with membranes containing higher amounts of borate additive.

Tuning thermal stability and electronic properties of germanium oxide on Ge(001) surface with the incorporation of nitrogen

The application of germanium as a channel material of transistors in near future requires an improved understanding of the interface between germanium and its potential passivation layer. In this study, we study effects of nitrogen incorporation on the thermal stability and electronic properties of GeOxNy/Ge interface by using high‐resolution X‐ray photoemission spectroscopy. We find that with the increasing nitrogen concentration in the GeOxNy films, the thermal stability can be increased, while the valence band offset with the Ge(001)substrate is decreased. First‐principles calculations further suggest that the unpaired p orbitals of nitrogen atoms induce electronic states near valence band edge, contributing to the reduction of the valence band offset. Our results provide a possibility to tune electronic and thermal properties of GeOxNy/Ge interface by controlling nitrogen concentrations during the growth.

Ab-Initio Studies of Acceptor Impurities and Stability of Complexes in Ge

The application of germanium (Ge) as a promising material for complementary metal-oxide semiconductors (CMOS) technology is attracting attention due to its narrow band gap, high carrier mobility and low voltage operations. Recent experimental and theoretical studies revealed that dopants in Ge cluster with vacancies forms with lower energies and contribute to low activation of dopants impurity in Ge. DFT electronic simulation have been used to provide concise information about the formation of defect clusters and complexes that influence diffusion mechanisms in Ge. Our main objective in this study is to use simulations based on ͑DFT to calculate the structural, electronic properties and interactions between acceptors and Ge in different configurations with a view to finding the most energetically stable configuration of various defect complexes in Ge. By means of density functional theory (DFT), we present ab-initio calculation of interactions between A (A: Be,Mg, Ca, Sr, Ba, Ga, In) vacancy complexes (A-VGe) and vacancy-interstitial complexes (A-VGeIA) in two configurations of the hexagonal (H) and tetrahedral (T) in Ge. These calculations employed a projector augmented wave (PAW) pseudopotentials within the generalized gradient approximation (GGA). The geometric structures and formation energies of A-VGe and A-VGeIA in both the T and H configurations for the neutral charge state were obtained. The formation energies of A-VGe were low and energectically favourable with Ga-VGe and Ca-VGe forming with the lowest formation energies at -1.24 and -0.38 eV respectively. For the A-VGeIA, the results of the H configuration were more energetically favourable and forms with lower formation energies than the T configuration. The Ca-VGeICa and Be-VGeIBe forms with the lowest formation energies of -2.59 and -1.49 eV respectively. The stability of the A-VGeIA and A-VGe complexes in Ge were obtained from their binding energies. The binding energies (Eb ) which are defined as the energy required to split up the defects cluster into well separated non-interacting defect is given as Eb = E(formation)(VGe) + E(formation)(AGe) - E(formation){defect-complex}, where E(formation)(VGe), E(formation)(AGe) and E(formation)(defect-complex) are the formation energies of the neutral charge state of the germanium vacancy, interstitials and defect-complexes. The above equation could be interpreted as the energy gain of the bonded structure with respect to the isolated components. Positive binding energies suggest that the defect complexes are stable and cannot easily dissociate. The calculated binding energies of both the A-VGe and the A-VGeIA displayed the ability of these complexes to form without dissociation. For the A-VGeIA, the H configuration forms with more favourable binding energies than the T configuration. In summary the detailed calculated results we have presented are expect to be useful in the process modeling of Ge-based devices.

Germanium oxide removal by citric acid and thiol passivation from citric acid-terminated Ge(100).

Many applications of germanium (Ge) are underpinned by effective oxide removal and surface passivation. This important surface treatment step often requires H-X (X = Cl, Br, I) or HF etchants. Here, we show that aqueous citric acid solutions are effective in the removal of GeOx. The stability of citric acid-treated Ge(100) is compared to HF and HCl treated surfaces and analyzed by X-ray photoelectron spectroscopy. Further Ge surface passivation was investigated by thiolation using alkane monothiols and dithiols. The organic passivation layers show good stability with no oxide regrowth observed after 3 days of ambient exposure.

Dangling-bond defects and hydrogen passivation in germanium

The application of germanium in complementary metal-oxide semiconductor technology is hampered by high interface-state densities. Using first-principles calculations, we investigate the effects of dangling bonds (DBs) and their interaction with hydrogen. We find that Ge DBs give rise to electronic levels below the valence-band maximum. They therefore occur exclusively in the negative charge state, explaining why they cannot be observed with electron spin resonance. The associated fixed charge is likely responsible for threshold-voltage shifts and poor performance of n-channel transistors. We also find that passivation of DBs by hydrogen will be ineffective because interstitial hydrogen is also stable exclusively in the negative charge state.

Some Applications of Germanium and Its Derivatives

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Some Applications of Germanium and its Derivatives

Some Applications of Germanium and its Derivatives

Germanium and Silicon Linking Strategies for Traceless Solid-Phase Synthesis.

Here we describe the development and application of germanium and silicon linkage strategies for the solid-phase synthesis of aromatic compounds, as demonstrated for 1,4-benzodiazepine derivatives. The metal-aryl bond that attaches the benzodiazepine to the polymeric support may be cleaved by electrophilic reagents such as H(+) and Br(2) to provide the corresponding substituted derivatives. A number of compounds have been prepared in good overall yield for the eight- or nine-step process. This approach can also be applied to the solid-phase synthesis of libraries of other classes of aromatic compounds.

The application of semiconductor detectors in nuclear structure physics

Various applications of germanium and silicon detectors to the detection of γ-rays and charged particles are described.

Potential of a positive test charge in germanium application to hydrogen

Abstract We present a potential map for a positive test charge in germanium. The contributions from the nuclei, the core charges, and the valence charges are considered. In this calculation a Born-Oppenheimer approximation is made and the response of the valence electrons to the presence of a positive charge is treated within the linear response theory. The relevance of our calculation to the problem of the hydrogen atom in germanium is discussed.

Application of germanium p-i-n detectors stable at room temperature in nondispersion X-ray analysis

We have proposed an X-ray spectrometer based on p-i-n detectors obtained by compensation of n-germanium by radiation defects. The detectors are stable at room temperature, with a thin entrance window and are made selfconsistent which noticeably simplifies the X-ray spectrometer. The advantage of this spectrometer over spectrometers with Si(Li) detectors lies in the possibility of analyzing the heavy elements on K-series. In defining W and Hg in ores the threshold sensitivity 4×10 −3% has been achieved.

Applications of Detectors in Low Energy Nuclear Physics

This review paper discusses new applications of detectors in low energy nuclear physics and emphasizes semiconductor particle detectors where new developments have had an outstanding influence on the nuclear physics which can be done. The paper includes an account of: new limits of detector resolution; a new method for measurement of gamma ray lifetimes; gamma-gamma angular correlation studies with multiple scintillation detectors; kinematic energy shift correction with radial position sensitive detectors; an improved particle identification system with multiple detectors; and the application of germanium to measurements of long-range charged particles. The paper also discusses present state-of-the-art limitations and possibilities in areas of particular importance to nuclear physics.

P-nJUNCTIONS IN SILICON AND GERMANIUM: PRINCIPLES, METALLURGY, AND APPLICATIONS: A. SEMI-CONDUCTOR ELECTRONICS

AbstractThe application of germanium and silicon to electronic devices, such as transistors, is becoming of major commercial importance in the electronics industry. Emphasis in the present review will be placed on the metallurgical aspects of germanium and silicon materials. However, since an appreciation of their application to electronics technology requires some background in the new and expanding field of semi-conductor electronics, the first part of the review will give an elementary survey of the important physical principles involved.

Rating and application of Germanium and Silicon rectifiers

GERMANIUM and silicon P-N junctions are becoming well known for their very nearly ideal combination of efficiency, flexibility, and reliability factors. Despite their high efficiency, the small internal losses of this type of rectifier cell are the chief criterion for rating and application.

Electronic Applications of Germanium

Electronic Applications of Germanium