Electronic Properties of Improved Amorphous Silicon-Germanium Alloys Deposited by a Low Temperature Hot Wire Chemical Vapor Deposition Process

2005 ◽  
Vol 862 ◽  
Author(s):  
Shouvik Datta ◽  
J. David Cohen ◽  
Yueqin Xu ◽  
A. H. Mahan
Keyword(s):  
Chemical Vapor Deposition ◽  
Electronic Properties ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Alloy Sample ◽  
Hot Wire ◽  
Novel Material ◽  
Amorphous Silicon Germanium

AbstractWe report novel material properties of a series of a-Si,Ge:H alloys grown by hot-wire chemical vapor deposition under low filament temperature (˜1800°C) and low substrate temperature (˜200-300°C). These alloys exhibit significantly improved electronic properties including low defect densities and sharp band tails (Urbach energies ≤ 45meV even for Ge fractions as high as 47at.%). On the other hand, comparisons of the transient photocapacitance and transient photocurrent spectra do not indicate very efficient hole collection in these materials. We found two distinct regimes of light-induced degradation in the alloy sample with 29at.% Ge fraction, possibly corresponding to the light induced increase of Ge and Si dangling bonds, respectively.

Hydrogenated Amorphous Silicon Germanium Alloys Grown by the Hot-Wire Chemical Vapor Deposition Technique

1998 ◽  
Vol 507 ◽  
Author(s):  
Brent P. Nelson ◽  
Yueqin Xu ◽  
D.L. Williamson ◽  
Bolko Von Roedern ◽  
Alice Mason ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Germanium Content ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous ◽  
Gas Ratio

ABSTRACTWe successfully grow high-quality hydrogenated amorphous-silicon-germanium alloys (a-SiGe:H) by the hot-wire chemical-vapor deposition (HWCVD) technique using silane and germane gas mixtures. These alloys display electronic properties as good as those grown by the plasma-enhanced chemical-vapor deposition (PECVD) technique, when comparing materials with the same optical bandgaps. However, we grow materials with good electrical properties at high deposition rates—up to 40 Å/s, compared to 1–4 Å/s for PECVD materials. Our alloys exhibit similar trends with increasing Ge content to alloys grown by PECVD. The defect density, the dark conductivity, and the degree of nanostructural heterogeneity (as measured by small-angle X-ray scattering) all increase with increasing germanium content in the alloy. The nanostructural heterogeneity displays a sharp transition between 9 at.% and 14 at.% germanium. PECVD- grown a-SiGe:H alloys exhibit a similar transition at 20 at.% Ge. The photoconductivity and the ambipolar diffusion length of the alloys decrease with increasing germanium content. For a fixed silane-to-germane gas ratio, all material properties improve substantially when increasing substrate temperature (Tsub) from 220°C to 375°C. Increasing Tsub also narrows the optical bandgap and lowers the hydrogen content in the alloys for the same germane-to-silane gas ratio.

scholarly journals Наращивание слоя Ge на структуру Si/SiO-=SUB=-2-=/SUB=-/Si (100) методом "горячей проволоки"

2020 ◽  
Vol 54 (10) ◽  
pp. 1129
Author(s):  
А.А. Сушков ◽  
Д.А. Павлов ◽  
С.А. Денисов ◽  
В.Ю. Чалков ◽  
Р.Н. Крюков ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Integrated Circuits ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
High Energy ◽  
Buffer Layers ◽  
Chemical Vapor Deposition Process ◽  
Hot Wire ◽  
Vapor Deposition Process

Ge/Si buffer layers grown at different temperatures on Si/SiO2/Si (100) substrates have been fabricated and studied. The Si buffer was grown via molecular beam epitaxy. The Ge layer was produced in a single stage via hot wire chemical vapor deposition process. Structural properties were investigated by high-resolution transmission electron microscopy and reflected high-energy electron diffraction. Such structures can be used in the future as a substrate for growth of high quality light-emitting structures compatible with silicon radiation-resistant integrated circuits. The paper shows the possibility of growth of a single crystal layer of Ge on Si/SiO2/Si (100) through a buffer layer of Si by the hot wire chemical vapor deposition process, and also demonstrates the difficulties that arise in the process of growth of Ge/Si layers on Si/SiO2/Si (100).

Effect of Ge Incorporation on Hydrogenated Amorphous Silicon Germanium Thin Films Prepared by Plasma Enhanced Chemical Vapor Deposition

2012 ◽  
Vol 569 ◽  
pp. 27-30
Author(s):  
Bao Jun Yan ◽  
Lei Zhao ◽  
Ben Ding Zhao ◽  
Jing Wei Chen ◽  
Hong Wei Diao ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous

Hydrogenated amorphous silicon germanium thin films (a-SiGe:H) were prepared via plasma enhanced chemical vapor deposition (PECVD). By adjusting the flow rate of GeH4, a-SiGe:H thin films with narrow bandgap (Eg) were fabricated with high Ge incorporation. It was found that although narrow Eg was obtained, high Ge incorporation resulted in a great reduction of the thin film photosensitivity. This degradation was attributed to the increase of polysilane-(SiH2)n, which indicated a loose and disordered microstructure, in the films by systematically investigating the optical, optoelectronic and microstructure properties of the prepared a-SiGe:H thin films via transmission, photo/dark conductivity, Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR) measurements. Such investigation provided a helpful guide for further preparing narrow Eg a-SiGe:H materials with good optoelectronic properties.

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