Thin Single Crystal Silicon on Oxide by Lateral Solid Phase Epitaxy of Amorphous Silicon and Silicon Germanium

2000 ◽  
Vol 609 ◽  
Author(s):  
Brian J. Greene ◽  
Joseph Valentino ◽  
Judy L. Hoyt ◽  
James F. Gibbons
Keyword(s):  
Single Crystal ◽  
Amorphous Silicon ◽  
Epitaxial Growth ◽  
Solid Phase ◽  
Single Crystal Silicon ◽  
Selective Etching ◽  
Lateral Growth ◽  
Crystal Silicon ◽  
Etch Stop ◽  
Etch Stop Layer

ABSTRACTThe fabrication of 250 Å thick, undoped, single crystal silicon on insulator by lateral solid phase epitaxial growth from amorphous silicon on oxide patterned (001) silicon substrates is reported. Amorphous silicon was grown by low pressure chemical vapor deposition at 525°C using disilane. Annealing at temperatures between 540 and 570°C is used to accomplish the lateral epitaxial growth. The process makes use of a Si/Si1-xGex/Si stacked structure and selective etching. The thin Si1-xGex etch stop layer (x=0.2) is deposited in the amorphous phase and crystallized simultaneously with the Si layers. The lateral growth distance of the epitaxial region was 2.5 μm from the substrate seed window. This represents a final lateral to vertical aspect ratio of 100:1 for the single crystal silicon over oxide regions after selective etching of the top sacrificial Si layer. The effects of Ge incorporation on the lateral epitaxial growth process are also discussed. The lateral epitaxial growth rate of 20% Ge alloys is enhanced by roughly a factor of three compared to the rate of Si films at an anneal temperature of 555°C. Increased random nucleation rates associated with Ge alloy films are shown to be an important consideration when employing Si1-xGex to enhance lateral growth or as an etch stop layer.

scholarly journals The Influence of Wire Speed on Phase Transitions and Residual Stress in Single Crystal Silicon Wafers Sawn by Resin Bonded Diamond Wire Saw

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 429
Author(s):  
Tengyun Liu ◽  
Peiqi Ge ◽  
Wenbo Bi
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Phase Transitions ◽  
Single Crystal ◽  
Amorphous Silicon ◽  
Silicon Wafer ◽  
Single Crystal Silicon ◽  
Silicon Wafers ◽  
Crystal Silicon ◽  
Diamond Wire

Lower warp is required for the single crystal silicon wafers sawn by a fixed diamond wire saw with the thinness of a silicon wafer. The residual stress in the surface layer of the silicon wafer is the primary reason for warp, which is generated by the phase transitions, elastic-plastic deformation, and non-uniform distribution of thermal energy during wire sawing. In this paper, an experiment of multi-wire sawing single crystal silicon is carried out, and the Raman spectra technique is used to detect the phase transitions and residual stress in the surface layer of the silicon wafers. Three different wire speeds are used to study the effect of wire speed on phase transition and residual stress of the silicon wafers. The experimental results indicate that amorphous silicon is generated during resin bonded diamond wire sawing, of which the Raman peaks are at 178.9 cm−1 and 468.5 cm−1. The ratio of the amorphous silicon surface area and the surface area of a single crystal silicon, and the depth of amorphous silicon layer increases with the increasing of wire speed. This indicates that more amorphous silicon is generated. There is both compressive stress and tensile stress on the surface layer of the silicon wafer. The residual tensile stress is between 0 and 200 MPa, and the compressive stress is between 0 and 300 MPa for the experimental results of this paper. Moreover, the residual stress increases with the increase of wire speed, indicating more amorphous silicon generated as well.

Three Generations of Solar Cells

2021 ◽  
Vol 1165 ◽  
pp. 113-130
Author(s):  
Romyani Goswami
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Single Crystal ◽  
Amorphous Silicon ◽  
Cost Reduction ◽  
High Stability ◽  
Single Crystal Silicon ◽  
Nanocrystalline Silicon ◽  
Crystal Silicon

In photovoltaic system the major challenge is the cost reduction of the solar cell module to compete with those of conventional energy sources. Evolution of solar photovoltaic comprises of several generations through the last sixty years. The first generation solar cells were based on single crystal silicon and bulk polycrystalline Si wafers. The single crystal silicon solar cell has high material cost and the fabrication also requires very high energy. The second generation solar cells were based on thin film fabrication technology. Due to low temperature manufacturing process and less material requirement, remarkable cost reduction was achieved in these solar cells. Among all the thin film technologies amorphous silicon thin film solar cell is in most advanced stage of development and is commercially available. However, an inherent problem of light induced degradation in amorphous silicon hinders the higher efficiency in this kind of cell. The third generation silicon solar cells are based on nano-crystalline and nano-porous materials. Hydrogenated nanocrystalline silicon (nc-Si:H) is becoming a promising material as an absorber layer of solar cell due to its high stability with high Voc. It is also suggested that the cause of high stability and less degradation of certain nc-Si:H films may be due to the improvement of medium range order (MRO) of the films. During the last ten years, organic, polymer, dye sensitized and perovskites materials are also attract much attention of the photovoltaic researchers as the low budget next generation PV material worldwide. Although most important challenge for those organic solar cells in practical applications is the stability issue. In this work nc-Si:H films are successfully deposited at a high deposition rate using a high pressure and a high power by Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RF PECVD) technique. The transmission electron microscopy (TEM) studies show the formations of distinct nano-sized grains in the amorphous tissue with sharp crystalline orientations. Light induced degradation of photoconductivity of nc-Si:H materials have been studied. Single junction solar cells and solar module were successfully fabricated using nanocrystalline silicon as absorber layer. The optimum cell is 7.1 % efficient initially. Improvement in efficiency can be achieved by optimizing the doped layer/interface and using Ag back contact.

The Effect of Starting Silicon Crystal Structure on Photoluminescence Intensity of Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
W. B. Dubbelday ◽  
S. D. Russell ◽  
K. L. Kavanagh
Keyword(s):  
Porous Silicon ◽  
Single Crystal ◽  
Amorphous Silicon ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Luminescent Materials ◽  
Photoluminescence Intensity ◽  
Crystal Silicon ◽  
Chemical Etch ◽  
Porosity Measurements

ABSTRACTIn previous work we reported that porous silicon (PS) films formed using a dilute HF:HNO3 chemical etch on polycrystalline, implant damaged single crystal, or amorphous starting material have luminescent characteristics that differ from PS fabricated on single crystal silicon1. Polycrystalline and implant damaged porous silicon exhibits brighter luminescence compared to single crystal silicon etched under identical conditions. No photoluminescence is detected from the porous amorphous silicon. In this work these effects are examined using HF:NaNO2 solutions with freely available NO2. The accelerated etching effects from work damage are reduced, and the PS from polycrystalline and implant damaged silicon luminesce with the same intensity as the PS from single crystal silicon. Again, etched amorphous silicon does not luminesce. TEM and EDX porosity measurements are used to determine the differences in structure and etching characteristics between the luminescent and non-luminescent materials.

High Concentrations of Erbium In Crystal Silicon by Thermal Or Ion-Beam-Induced Epitaxy of Erbium-Implanted Amorphous Silicon

1993 ◽  
Vol 301 ◽  
Author(s):  
J. S. Custer ◽  
A. Polman ◽  
E. Snoeks ◽  
G. N. van den Hoven
Keyword(s):  
Single Crystal ◽  
Amorphous Silicon ◽  
Solid Phase ◽  
Ion Beam ◽  
Solid Phase Epitaxy ◽  
Crystal Silicon ◽  
Epitaxial Crystallization ◽  
Amorphous Si ◽  
High Concentrations ◽  
Er Doped

ABSTRACTSolid phase epitaxy and ion-beam-induced epitaxial crystallization of Er-doped amorphous Si are used to incorporate high concentrations of Er in crystal Si. During solid phase epitaxy, substantial segregation and trapping of Er is observed, with maximum Er concentrations trapped in single crystal Si of up to 2 × 1020 /cm3. Ion-beam-induced regrowth results in very little segregation, with Er concentrations of more than 5 × 1020 /cm3 achievable. Photoluminescence from the incorporated Er is observed.

Fast Scanned Energy Beam Induced Explosive Crystallization of Ion Implantation Amorphized Poly and Single Crystal Silicon Substrates

1981 ◽  
Vol 4 ◽  
Author(s):  
M. Lerme ◽  
T. Ternisien D'ouville ◽  
Duy-Phach Vu ◽  
A. Perio ◽  
G.A. Rozgonyi ◽  
...  
Keyword(s):  
Single Crystal ◽  
Solid Phase ◽  
Single Crystal Silicon ◽  
Grain Structure ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Energy Beam ◽  
Glass Substrates ◽  
Explosive Crystallization ◽  
Si Films

ABSTRACTExplosive crystallisation induced by an electron beam and by a CW Ar+ laser operating in fast scanning mode is observed for the first time on amorphized silicon layers created by implantation on either polycrystalline films deposited on Si02 or single crystal silicon substrates. The grain structure in the explosive crescents is studied by preferential chemical etching in conjunction with Nomarski optical microscopy, SEM and TEM. The results are similar to the so-called solid-phase explosive crystallization previously observed in a-Si films deposited on glass substrates.

Microwave Activation of Dopants & Solid Phase Epitaxy in Silicon

2007 ◽  
Vol 989 ◽  
Author(s):  
Douglas C. Thompson ◽  
J. Decker ◽  
T. L. Alford ◽  
J. W. Mayer ◽  
N. David Theodore
Keyword(s):  
Single Crystal ◽  
Microwave Heating ◽  
Rutherford Backscattering Spectrometry ◽  
Solid Phase ◽  
Single Crystal Silicon ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Microwave System

AbstractMicrowave heating is used to activate solid phase epitaxial re-growth of amorphous silicon layers on single crystal silicon substrates. Layers of single crystal silicon were made amorphous through ion implantation with varying doses of boron or arsenic. Microwave processing occurred inside a 2.45 GHz, 1300 W cavity applicator microwave system for time-durations of 1-120 minutes. Sample temperatures were monitored using optical pyrometery. Rutherford backscattering spectrometry, and cross-sectional transmission electron microscopy were used to monitor crystalline quality in as-implanted and annealed samples. Sheet resistance readings show dopant activation occurring in both boron and arsenic implanted samples. In samples with large doses of arsenic, the defects resulting from vacancies and/or micro cluster precipitates are seen in transmission electron micrographs. Materials properties are used to explain microwave heating of silicon and demonstrate that the damage created in the implantation process serves to enhance microwave absorption.

Sign in / Sign up

Export Citation Format

Share Document