Investigation of the Promotion Effect of Germane in Low Temperature Uhv-Cvd Silicon

1987 ◽  
Vol 102 ◽  
Author(s):  
Kevin J. Uram ◽  
Bernard S. Meyerson
Keyword(s):  
Low Temperature ◽  
Silicon Germanium ◽  
Crystalline Silicon ◽  
Defect Density ◽  
Single Crystal Silicon ◽  
Gas Mixture ◽  
Crystal Silicon ◽  
Germanium Silicon ◽  
Kinetics Of ◽  
Silicon Germanium Alloys

ABSTRACTHigh quality, low defect density, single crystalline silicon/germanium alloys have been grown on Si(100) substrate wafers in a low temperature UHV-CVD reactor. Using a silane/germane gaseous source, the growth rate of the epitaxial layer increases from 4 angstroms/minute with no germane present to 82 angstroms/minute with 12.7% germane present in the reaction gas mixture at 550C. The germanium/silicon ratio in the deposited alloy is a factor of two greater than the germane/silane ratio in the reaction gas mixture. The kinetics of this effect are studied and correlation to UHV hydrogen thermal desorption from single crystal silicon-germanium alloys are made.

Selective and low temperature synthesis of polycrystalline diamond

1991 ◽  
Vol 6 (6) ◽  
pp. 1278-1286 ◽  
Author(s):  
R. Ramesham ◽  
T. Roppel ◽  
C. Ellis ◽  
D.A. Jaworske ◽  
W. Baugh
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Substrate Temperature ◽  
Microwave Plasma ◽  
Diamond Particle ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Crystal Silicon ◽  
Diamond Thin Films

Polycrystalline diamond thin films have been deposited on single crystal silicon substrates at low temperatures (⋚ 600 °C) using a mixture of hydrogen and methane gases by high pressure microwave plasma-assisted chemical vapor deposition. Low temperature deposition has been achieved by cooling the substrate holder with nitrogen gas. For deposition at reduced substrate temperature, it has been found that nucleation of diamond will not occur unless the methane/hydrogen ratio is increased significantly from its value at higher substrate temperature. Selective deposition of polycrystalline diamond thin films has been achieved at 600 °C. Decrease in the diamond particle size and growth rate and an increase in surface smoothness have been observed with decreasing substrate temperature during the growth of thin films. As-deposited films are identified by Raman spectroscopy, and the morphology is analyzed by scanning electron microscopy.

Electrical Properties of Polycrystalline-Silicon Thin Films for VLSI

1986 ◽  
Vol 71 ◽  
Author(s):  
T I Kamins
Keyword(s):  
Electrical Properties ◽  
Integrated Circuits ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Crystalline Silicon ◽  
Single Crystal Silicon ◽  
Active Regions ◽  
Crystal Silicon ◽  
Polysilicon Film

AbstractThe electrical properties of polycrystalline silicon differ from those of single-crystal silicon because of the effect of grain boundaries. At low and moderate dopant concentrations, dopant segregation to and carrier trapping at grain boundaries reduces the conductivity of polysilicon markedly compared to that of similarly doped single-crystal silicon. Because the properties of moderately doped polysilicon are limited by grain boundaries, modifying the carrier traps at the grain boundaries by introducing hydrogen to saturate dangling bonds improves the conductivity of polysilicon and allows fabrication of moderate-quality transistors with their active regions in the polycrystalline films. Removing the grain boundaries by melting and recrystallization allows fabrication of high-quality transistors. When polysilicon is used as an interconnecting layer in integrated circuits, its limited conductivity can degrade circuit performance. At high dopant concentrations, the active carrier concentration is limited by the solid solubility of the dopant species in crystalline silicon. The current through oxide grown on polysilicon can be markedly higher than that on oxide of similar thickness grown on singlecrystal silicon because the rough surface of a polysilicon film enhances the local electric field in oxide thermally grown on it. Consequently, the structure must be controlled to obtain reproducible conduction through the oxide. The differences in the behavior of polysilicon and single-crystal silicon and the limited electrical conductivity in polysilicon are having a greater impact on integrated circuits as the feature size decreases and the number of devices on a chip increases in the VLSI era.

Thermally-Induced Change of Conductivity and Defect Density in Amorphous Silicon-Germanium Alloys

1990 ◽  
Vol 192 ◽  
Author(s):  
Tatsuo Shimizu ◽  
Xixiang Xu ◽  
Hiroyuki Sasaki ◽  
Hui Yan ◽  
Akiharu Morimoto ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Defect Density ◽  
Equilibrium Temperature ◽  
Exponential Form ◽  
Thermally Induced ◽  
Neutral Defect ◽  
Fast Cooling ◽  
Amorphous Silicon Germanium ◽  
Silicon Germanium Alloys

ABSTRACTThermally-induced metastable phenomena in amorphous silicon-germanium alloys were studied by conductivity and ESR measurements. Fast cooling from 250 °C reduced both dark- and photo-conductivities by a factor of 3–4 while the neutral defect density remained unchanged. Thermally-induced change in conductivity relaxed towards equilibrium with a stretched exponential form. The thermal equilibrium temperature was found to be roughly proportional to the optical gap for a–Si:H, a–Sii−xCx:H, a–Si1−xNx:H and a–Si1−xGex:H:F.

From the Casimir Limit to Phononic Crystals: 20 Years of Phonon Transport Studies Using Silicon-on-Insulator Technology

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Amy M. Marconnet ◽  
Mehdi Asheghi ◽  
Kenneth E. Goodson
Keyword(s):  
Room Temperature ◽  
Crystalline Silicon ◽  
Phonon Dispersion ◽  
Single Crystal Silicon ◽  
Phonon Transport ◽  
Silicon On Insulator ◽  
Boundary Scattering ◽  
Porous Films ◽  
Crystal Silicon ◽  
20 Nm

Silicon-on-insulator (SOI) technology has sparked advances in semiconductor and MEMs manufacturing and revolutionized our ability to study phonon transport phenomena by providing single-crystal silicon layers with thickness down to a few tens of nanometers. These nearly perfect crystalline silicon layers are an ideal platform for studying ballistic phonon transport and the coupling of boundary scattering with other mechanisms, including impurities and periodic pores. Early studies showed clear evidence of the size effect on thermal conduction due to phonon boundary scattering in films down to 20 nm thick and provided the first compelling room temperature evidence for the Casimir limit at room temperature. More recent studies on ultrathin films and periodically porous thin films are exploring the possibility of phonon dispersion modifications in confined geometries and porous films.

Sign in / Sign up

Export Citation Format

Share Document