Silane Flow Rate Research Articles

A new look at an explanation of band gap of PECVD grown a-Si:H thin films using absorption spectra, spectroscopic ellipsometry, Raman, and FTIR spectrosopy

Amorphous silicon is seen to be among the most promising materials for solar cell applications because of its higher temperature coefficient of resistance, adjustable forbidden-band gap, enhanced optical absorption, and capacity to reduce solar module costs. Changes in deposition rate, absorption coefficient and optical band gap of a-Si:H films with varying silane flow rate show that SiH4 molecules density influence the plasma growth process. Silane flow rate affects the percentage of silicon atoms during processing. The deposition rate of a-Si: H films increased from 14.36 nm/min to 15.97 nm/min by increasing silane flow rate from 25 sccm to 45 sccm. Broadening of optical band is observed. Films deposited at 35 sccm of silane flow rate shows the higher absorption coefficient. All films are characterized by FTIR, Raman spectroscopy, spectroscopic ellipsometry and optical absorption to understand the changes in band gap. The band gap Eg of all films is correlated with microstructure factor, Q factor, bond angle deviation Δθ and width of Si–H2 mode to analyse the effect of defects, disorders and microvoids.

High‐Quality Nonpolar a‐Plane AlGaN Film Grown on Si‐Doped AlN Template by Metal Organic Chemical Vapor Deposition

High crystalline quality and flat a‐plane aluminum gallium nitride (AlGaN) films are obtained on Si‐doped AlN templates with a moderate silane (SiH4) flow rate by metal‐organic chemical vapor deposition (MOCVD). The effects of the SiH4 flow rate on the surface morphology, crystalline quality, stress state, and optical property of a‐plane AlN templates and AlGaN films are comprehensively investigated. As the SiH4 flow rate increases from 0 to 7.0 nmol min−1, the full width at half maximum of X‐ray rocking curve values along [0001]/[1–100] directions for the AlGaN films are monotonically reduced to 1124/1143 arcsec. Meanwhile, the surface root mean square roughness value is decreased to 0.88 nm. These achievements are attributed to the suppression of the anisotropy degrees and in‐plane stress of AlN templates. In addition, an excess SiH4 flow rate leads to deteriorated surface morphologies and increased basal plane stacking fault (BPSF) densities for both AlN and AlGaN films. This work suggests that doping AlN layers with an appropriate SiH4 flow rate is a promising route to obtain high‐quality a‐plane AlGaN films for efficient nonpolar deep ultraviolet (DUV) devices.

Metalorganic chemical vapor deposition of (100) β-Ga2O3 on on-axis Ga2O3 substrates

Metalorganic chemical vapor deposition (MOCVD) growths of β-Ga2O3 on on-axis (100) Ga2O3 substrates are comprehensively investigated. Key MOCVD growth parameters including growth temperature, pressure, group VI/III molar flow rate ratio, and carrier gas flow rate are mapped. The dependence of the growth conditions is correlated with surface morphology, growth rate, and electron transport properties of the MOCVD grown (100) β-Ga2O3 thin films. Lower shroud gas (argon) flow is found to enhance the surface smoothness with higher room temperature (RT) electron Hall mobility. The growth rate of the films decreases but with an increase of electron mobility as the VI/III molar flow rate ratio increases. Although no significant variation on the surface morphologies is observed at different growth temperatures, the general trend of electron Hall mobilities are found to increase with increasing growth temperature. The growth rates reduce significantly with uniform surface morphologies as the chamber pressure increases. By tuning the silane flow rate, the controllable carrier concentration of (100) β-Ga2O3 thin films between low-1017 cm−3 and low-1018 cm−3 was achieved. Under optimized growth condition, an (100) β-Ga2O3 thin film with RMS roughness value of 1.64 nm and a RT mobility of 24 cm2/Vs at a carrier concentration of 7.0 × 1017 cm−3 are demonstrated. The mobilities are primarily limited by the twin lamellae and stacking faults defects generated from the growth interface. Atomic resolution scanning transmission electron microscopy reveals the formation of twin boundary defects in the films, resulting in the degradation of crystalline quality. Results from this work provide fundamental understanding of the MOCVD epitaxy of (100) β-Ga2O3 on on-axis Ga2O3 substrates and the dependence of the material properties on growth conditions. The limitation of electron transport properties of the (100) β-Ga2O3 thin films below 25 cm2/Vs is attributed to the formation of incoherent boundaries (twin lamellae) and stacking faults grown along the on-axis (100) crystal orientation.

Influence of silane flow rate on the structural and optical properties of GaN nanowires with multiple-quantum-shells

In this study, we discuss the influence of SiH4 flow rates on the structural and optical properties of GaN nanowires (NWs) with multiple-quantum-shells (MQSs). To this end, we prepared two n-GaN core NW samples with different SiH4 flow rates. Subsequently, MQS active layers of the same structure were grown on each n-GaN core NW under identical growth conditions. The samples were characterized by scanning electron microscopy, scanning transmission electron microscopy, energy-dispersive X-ray, and cathodoluminescence (CL) mapping. From the experimental results, we ascertained that a Si-rich layer was created between the sidewall of the NWs and MQSs, in which the number of Si atoms was mainly determined by the SiH4 flow rate. These Si atoms diffused into the MQSs during the growth, and significantly impacted the structural and optical properties, such as the shape and crystalline quality of the MQSs and NWs, and the CL intensity of the MQSs. On the basis of experimental results, we conclude that the SiH4 flow rate during the NW growth plays a critical role in the performance of an MQS-based optoelectronic semiconductor device.

Temperature-dependent electrical and optical studies on nonpolar a-plane GaN thin films with various Si-doping levels

The electrical and optical properties of nonpolar a-plane GaN films with various silane flow rates were studied intensively utilizing temperature-dependent Hall-effect and photoluminescence measurements. The electron Hall mobility was found to change from increase to decrease while the silane flow beyond 16.06 nmol/min. It was inferred that the primary scattering mechanism of Si-doped GaN transferred from ionized impurity to thermal lattice vibration with the temperature over 450 K as more disordered lattice vibration was caused by Si doping. Meanwhile, the band-gap of nonpolar a-plane GaN film demonstrated a 32.56 meV narrowing owing to the Si-doping induced band-gap narrowing effect. Moreover, the basal stacking faults (BSFs) and Ga vacancy-related emission were evidently suppressed, and a decrease of 12.02% for BSFs density was achieved with Si-doping.

Effect of discharge power and silicon content on optical and mechanical properties of carbon-rich amorphous silicon carbide films obtained by PECVD

We studied optical and mechanical properties of a-SixC1-x:H films prepared by the PECVD technique from the mixture of CH4, SiH4, H2 and Ar. RF discharge power and silane flow rate were chosen as parameters of the film deposition process that allowed to vary film properties. It was shown that variations of silane flow rate (10, 20 sccm) and discharge power in the 100–300 W range allow to obtain films with the following characteristics: optical bandgap 2.5–4.1 eV; refractive index of 1.8–2.1; hardness (H) 8.6–14.8 GPa; Young modulus (E) 64–143 GPa. The film deposition rate varied from 10 to 35 nm/min. By selecting deposition regimes, we deposited films with high ratio between film hardness and Young modulus (H/E = 0.13). The variations of optical and mechanical properties of the films by changing discharge power and silane flow are interpreted within a model accounting film composition and phase-structural transformations. Good combination of optical and mechanical properties of the developed films makes them promising for application as protective, passivation and anti-reflection coatings.

Effect of SiH<sub>4 </sub>Flow Rates on the Structures and Properties of Si-Rich Silicon Nitride Films Prepared by Hot Wire Chemical Vapor Deposition

Silicon-rich silicon nitride thin films were deposited on the P type (100) of silicon and Corning7059 glass by hot-wire chemical vapor deposition method using SiH4 and NH3 as reaction gas source. The effects of SiH4 flow rate on the structures and optical properties of the thin films were studied under optimizing other deposition parameters. The structures, band gap width and surface morphology of the thin films were characterized by Fourier transform infrared absorption spectroscopy (FTIR), ultraviolet-visible (UV-VIS) light transmittance spectra and scanning electron microscope (SEM), respectively. The experiment results show that, with increasing of the SiH4 flow rate, the content of N and Si atoms in the thin films increases, and the Si-N bond density increases gradually, and the optical band gap of the films shows a trend of increasing. When the silane flow rate is less than 0.9sccm, there is no Si-H bond stretching vibration absorption peak, and silicon atoms mainly bond with nitrogen atoms. As the SiH4 flow rate decreases, silicon clusters embedded in silicon nitride matrix gradually become smaller. When SiH4 flow rate is 0.4sccm, we prepared the silicon cluster nanoparticles with an average diameter of about 50nm embedded in silicon nitride thin films matrix. Therefore, properly reduction of the SiH4 flow rate is favorable for preparing the smaller silicon cluster nanoparticles in silicon rich silicon nitride thin films. The results lay the foundation for the preparation of silicon quantum dots thin film materials.

Material Structure and Mechanical Properties of Silicon Nitride and Silicon Oxynitride Thin Films Deposited by Plasma Enhanced Chemical Vapor Deposition

Silicon nitride and silicon oxynitride thin films are widely used in microelectronic fabrication and microelectromechanical systems (MEMS). Their mechanical properties are important for MEMS structures; however, these properties are rarely reported, particularly the fracture toughness of these films. In this study, silicon nitride and silicon oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) under different silane flow rates. The silicon nitride films consisted of mixed amorphous and crystalline Si3N4 phases under the range of silane flow rates investigated in the current study, while the crystallinity increased with silane flow rate in the silicon oxynitride films. The Young’s modulus and hardness of silicon nitride films decreased with increasing silane flow rate. However, for silicon oxynitride films, Young’s modulus decreased slightly with increasing silane flow rate, and the hardness increased considerably due to the formation of a crystalline silicon nitride phase at the high flow rate. Overall, the hardness, Young modulus, and fracture toughness of the silicon nitride films were greater than the ones of silicon oxynitride films, and the main reason lies with the phase composition: the SiNx films were composed of a crystalline Si3N4 phase, while the SiOxNy films were dominated by amorphous Si–O phases. Based on the overall mechanical properties, PECVD silicon nitride films are preferred for structural applications in MEMS devices.

Characterization of Epitaxial Heavily Doped Silicon Regions Formed by Hot-Wire Chemical Vapor Deposition Using Micro-Raman and Microphotoluminescence Spectroscopy

We report on the characterization of heavily boron doped epitaxial silicon regions grown in a hot-wire chemical vapor deposition tool, using micro-Raman and photoluminescence spectroscopy. In particular, the use of this approach for emitter fabrication in an interdigitated back contact silicon solar cell is studied, by analyzing its suitability concerning selective growth, uniformity, anneal time, and luminescent defects. We show that by reducing the silane flow rate, both the required postanneal time and intensity of defect luminescence are reduced. Furthermore, we show that selective area growth does not affect either the quality of the films or the sharpness of the resulting lateral doping profile. The uniformity of the doping is shown to be better than that achieved using laser doping.

Effects of Hydrogen-Dilution on Opto-Structural Properties of Hot-wire CVD Grown a-Si:H/nc-Si:H Multilayer for Photovoltaics

The multilayered thin film structure of amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) provides the possibility of bandgap tuning for fabrication of multijunction solar cells. This paper communicates a detailed analysis of optical and structural properties of a-Si:H/nc-Si:H multilayer thin films by hot-wire chemical vapor deposition at low hydrogen (H2) and silane (SiH4) flow rates. A set of multilayer films with 25 bilayers of a-Si:H/nc-Si:H are prepared using different hydrogen-dilution of SiH4 in the alternating nc-Si:H layers. The first and the second order Raman scattering studies reveal the presence of mixed phases of silicon in the nc-Si:H layers. Raman and XRD investigation of the films confirm the presence of different sizes of the silicon nanocrystals. The optical spectroscopic analysis instead of FTIR analysis of multilayer films is utilized uniquely to determine the hydrogen content in the a-Si:H/nc-Si:H multilayers and is related to the amorphous phase of the films. No significant change in hydrogen content is observed and the amorphous phase is found to decrease with increase in hydrogen dilution. Further, no quantum size effect (QSE) was observed due to the large growth time of nc-Si:H layers. Thus the experimental result shows that the bandgap of multilayer films decreases due to reduction in amorphous silicon phase, ineffective QSE and relative loss of hydrogen content.

Unravelling a simple method for the low temperature synthesis of silicon nanocrystals and monolithic nanocrystalline thin films

In this work, we present new results on the plasma processing and structure of hydrogenated polymorphous silicon (pm-Si:H) thin films. pm-Si:H thin films consist of a low volume fraction of silicon nanocrystals embedded in a silicon matrix with medium range order, and they possess this morphology as a significant contribution to their growth comes from the impact on the substrate of silicon clusters and nanocrystals synthesized in the plasma. Quadrupole mass spectrometry, ion flux measurements, and material characterization by transmission electron microscopy (TEM) and atomic force microscopy all provide insight on the contribution to the growth by silicon nanocrystals during PECVD deposition. In particular, cross-section TEM measurements show for the first time that the silicon nanocrystals are uniformly distributed across the thickness of the pm-Si:H film. Moreover, parametric studies indicate that the best pm-Si:H material is obtained at the conditions after the transition between a pristine plasma and one containing nanocrystals, namely a total gas pressure around 2 Torr and a silane to hydrogen ratio between 0.05 to 0.1. From a practical point of view these conditions also correspond to the highest deposition rate achievable for a given RF power and silane flow rate.

No Significant Effect of Phosphorous Doping on the Electrochemical Performance of Silicon-Carbon Composite Anodes for Li-ion Batteries

SUMMARY Using an industry-relevant method of production we have demonstrated production of doped silicon nanoparticles for Li-ion batteries. The particles have been characterized and tested in Li-ion battery half-cells for demonstration of the performance as Li ion storage material in the anode. In this presentation we will show the results regarding the characterization of the particles as well as the performance results of the material in Li-ion half cells. BACKGROUND The use of silicon as part of the anode in Li-ion batteries enhances the potential storage capacity greatly. While the graphite anode used in standard Li-ion batteries has a theoretical capacity of 372 mAh/g, the theoretical capacity for Si is 3,572 mAh/g [1]. However, to be able to absorb the sufficient amount of Li ions reversibly, the silicon material needs to be nanostructured [2]. EXPERIMENTAL IFE has earlier demonstrated production of silicon particles prepared using a silane-based free-space reactor, which allows control of particle size distribution and crystallinity and a high production capacity [3]. In this work, the setup was modified to allow for introduction of phosphine gas in the production process. The intention was to introduce phosphorous dopant atoms to modify the electrical conductivity of the silicon material. The current particles were produced with a silane flow rate of 5 slm, and 5 slm of 3% phosphine diluted in He. Thus, the P concentration in the process gases was 3% with respect to Si. The production rate at 100% yield would be about 400 g/h, while the product recovered from the process typically was between 100 and 200 g/h. The processing temperature was varied from 475 °C to 600 °C to produce particles with different properties. All electrochemical tests were performed in a crimped 2032 coin cell with lithium metal used as a counter electrode, with a polymer separator (Celgard 3401) and 1 M LiPF6 in 1:1 EC/DMC electrolyte (LP30, BASF). For some experiments, 10 wt% fluoroethylene carbonate (FEC) was used as electrolyte additive. The cells were cycled at 25 °C between 0.05 and 1.0 V with a constant C-rate of C/10 (after initial 3 cycles at C/20) using an Arbin Battery cycler (Arbin Instruments). RESULTS AND CONCLUSIONS The phosphorus content of the particles was by inductively coupled plasma mass spectrometry (ICP-MS) and energy-dispersive x-ray spectroscopy (EDS) measured to be in the range of 1.7-1.8% with respect to silicon. Thus, it seems that the utilization of the phosphine is not complete, or phosphorous binds to materials which are not recovered from the production process. The particle size distribution was centered around 600 nm as measured by laser scattering in a Malvern Mastersizer 2000. SEM and TEM revealed that the particles consisted of aggregates of spherical silicon particles with a primary particle size of 50-400 nm. X-ray diffraction showed that we could produce amorphous or crystalline particles depending on the temperature of the process. Cycling of the particles in lithium battery half cells showed a life time of about 300 cycles for doped and undoped particles. Some measurements indicate a better conductivity of the doped material but the results were not conclusive. The cells were cycled with a limited capacity regime where the capacity was set to 1000 mAh/g(Si) and thus the end-voltage could vary. The most pronounced difference in the cycling performance between doped and undoped silicon particles was a shift in the increase in end voltage for the doped particles: While end-voltage increased from 0.4 V to 0.6 V over the first 25 cycles, this development is stretched out over the first 50 cycles or more for doped particles. See the attached figure for further details.

SiyGe1−x−ySnx films grown on Si using a cold-wall ultrahigh-vacuum chemical vapor deposition system

Silicon germanium tin alloys were grown directly on Si substrates using a cold-wall ultrahigh-vacuum chemical vapor deposition system at 300 °C, where commercially available precursors of silane, germane, and stannic chloride were used to grow the epitaxial layers. The crystallinity and growth quality of the SiyGe1−x−ySnx films were investigated through material characterization methods including x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and transmission electron microscopy. Rutherford backscattering measurements show that 2%–5% of the Sn and 3%–5% of the Si were successfully incorporated. Investigation of the material growth parameters shows that a flow rate of stannic chloride higher than 1 sccm results in etching of the film, while an increase in the silane flow rate results in amorphous film growth. The photoluminescence study shows clear emission peaks ascribed to direct and indirect bandgap transitions, which are in agreement with theoretical calculations.

Atomic and electronic structure of amorphous and nanocrystalline layers of semi-insulating silicon produced by chemical-vapor deposition at low pressures

Semi-insulating silicon SIPOS layers are prepared on single-crystal silicon substrates of two orientations Si (111) and Si (100) by chemical-vapor deposition at a reduced pressure in a horizontal hot-wall reactor at a temperature of 638°C and pressure of P = 20 Pa with a silane flow rate of 8 L/h and the addition of nitrous oxide into the reactor environment. Electronic-structure and phase-composition investigations by ultrasoft X-ray emission spectroscopy (USXES) and X-ray diffraction (XRD) methods show that the addition of nitrous-oxide gas into the reactor environment results in the formation of amorphous silicon layers. The layer-by-layer-phase analysis via USXES of the SIPOS samples to a depth of 120 nm without destruction indicates the predominance of oxide phases in the sample surface layers with a thickness of about 10 nm. The general content of unbound and bound oxygen of less than about 10%, below which nanocrystalline silicon is formed with an average particle size of 60–70 nm, can be considered as some conditional crystallization threshold of SIPOS amorphous layers.

Passivation study of multi-crystalline silicon wafer with i-a-Si:H layer deposited by HWCVD

Heterojunction solar cells (a-Si:H/c-Si) are interface dominated devices and hence suppression of charge carrier recombination at the a-Si:H/c-Si interface is a very important aspect. Till now, all efforts and results have been obtained on mono-crystalline silicon. It would be very important from the technological point of view if similar high efficiency devices are realized on cheaper mc-Si wafers. The aim of this work is to study the passivation effect on mc-Si wafer by i-a-Si:H thin layer. The i-a-Si:H thin passivation layer is deposited on mc-Si wafer by Hot-Wire CVD at various filament temperature and silane flow rates. The passivation effect has been studied by effective carrier lifetime measurement and implied open circuit voltage.

Plasma–surface interaction during low pressure microcrystalline silicon thin film growth

The role of plasma–surface interactions during microcrystalline silicon thin film growth has been studied under low power–low pressure conditions, and a correlation between the plasma–surface interactions and material properties has been provided. The atomic hydrogen flux, inferred by optical emission spectroscopy measurements, has been investigated. The hydrogen-to-silicon growth flux resulted in a ratio of 25 : 140 for the amorphous-to-mixed phase transition, whereas it increased to 40 : 170 for the mixed phase-to-microcrystalline phase transition. The ion contribution to the plasma–surface interaction has also been investigated. For this purpose, a capacitive probe has been implemented locally for direct measurement of the ion flux. For the amorphous-to-microcrystalline phase transition the ion-to-silicon growth flux ratio has been determined to increase from 0.15 to 1, two orders of magnitude smaller than the atomic hydrogen-to-silicon growth flux ratio. The ion energy has been measured with a retarding field energy analyser, which allowed determination of the ion-energy distribution as a function of the silane flow rate. Average ion energies of 15–20 eV have been found for a decreasing silane flow rate, thereby indicating the limited energy transfer to the surface. The main effect caused by the ion arrival at the surface is a locally induced thermal spike enhancing the radical surface diffusion. No prominent detrimental effect, i.e. Si surface or bulk displacement requiring energies greater than 18 eV and 40 eV respectively, or sputtering occurring above 50 eV, has been observed.

Defects and stresses in MBE-grown GaN and Al0.3Ga0.7N layers doped by silicon using silane

The electric and structural characteristics of silicon-doped GaN and Al0.3Ga0.7N layers grown by molecular beam epitaxy (MBE) using silane have been analyzed by the Hall effect, Raman spectroscopy, and high-resolution X-ray diffractometry. It is established that the electron concentration linearly increases up to n = 4 × 1020 cm−3 with an increase in the silane flow rate for GaN:Si, whereas the corresponding dependence for Al0.3Ga0.7N:Si is sublinear and the maximum electron concentration is found to be n = 4 × 1019 cm−3. X-ray measurements of sample macrobending indicate a decrease in biaxial compressive stress with an increase in the electron concentration in both GaN:Si and Al0.3Ga0.7N:Si layers. The parameters of the dislocation structure, estimated from the measured broadenings of X-ray reflections, are analyzed.

Effect of silane/hydrogen ratio on microcrystalline silicon thin films by remote inductively coupled plasma

Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by remote low frequency inductively coupled plasma (ICP) chemical vapor deposition system, and the effect of silane/hydrogen ratio on the microstructure and electrical properties of μc-Si:H films was systematically investigated. As silane/hydrogen ratio increases, the crystalline volume fraction Fc decreases and the ratio of the intensity of (220) peak to that of (111) peak drops as silane flow rate is increased. The FTIR result indicates that the μc-Si:H films prepared by remote ICP have a high optical response with a low hydrogen content, which is in favor of reducing light-induced degradation effect. Furthermore, the processing window of the phase transition region for remote ICP is much wider than that for typical ICP. The photosensitivity of μc-Si:H films can exceed 100 at the transition region and this ensures the possibility of the fabrication of microcrystalline silicon thin film solar cells with a open-circuit voltage of about 700 mV.

Effect of silane flow rate on structural, electrical and optical properties of silicon thin films grown by VHF PECVD technique

Hydrogenated silicon thin films deposited by VHF PECVD process for various silane flow rates have been investigated. The silane flow rate was varied from 5 sccm to 30 sccm, maintaining all other parameters constant. The electrical, structural and optical properties of these films were systematically studied as a function of silane flow rate. These films were characterized by Raman spectroscopy, Scanning Electron Microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and UV–visible (UV–Vis) spectroscopy. Different crystalline volume fraction (22%–60%) and band gap (∼1.58 eV–∼1.96 eV) were achieved for silicon thin films by varying the silane concentration. A transition from amorphous to nanocrystalline silicon has been confirmed by Raman and FTIR analysis. The film grown at this transition region shows the high conductivity in the order of 10−4 Ω−1 cm−1.

Multi-response optimization of ultrathin poly-SiGe films characteristics for Nano-ElectroMechanical Systems (NEMS) using the grey-Taguchi technique

Poly-SiGe can be used for monolithically integrating Micro/Nano-ElectroMechanical Systems (M/NEMS) with its driving circuitry in a MEMS-last approach. For these applications, it is important to have poly-SiGe films with a low tensile stress, a low resistivity and a high deposition rate. This paper presents a systematic procedure for the simultaneous optimization of these 3 properties for CVD deposited ultrathin (100±5nm) poly-SiGe films by using the grey-Taguchi approach. Seven process variables were identified as important parameters for controlling the deposition process and the resulting film properties, namely the deposition temperature, the silane, germane, diborane and hydrogen flow rate, the chamber pressure and the shower head-heater spacing. By using 4 different levels for each process variable, 32 unique experiments were defined based on an L32 orthogonal array. The optimal combination of process parameters was determined by applying the grey relational analysis (GRA) for multiple performance characteristics. The analysis of variance (ANOVA) showed that the deposition temperature has the highest influence on the multi-performance characteristics (contributing ∼41%). The projected optimized process resulted in a 100nm-thick poly-SiGe film with a tensile stress of 43MPa, a very low resistivity of 1.39mΩ-cm, a deposition rate of 0.34nm/s, a germanium concentration of 87%, a cauliflower surface morphology with a root-mean-square roughness of 4.2nm, an elastic modulus of 101±0.81GPa and a strain gradient of −2.0×10−2/μm. The optimized film is expected to be desirable as structural layer for M/NEMS applications such as nanoswitches, nanoresonators, biosensors etc.