High phosphorus doping of epitaxial silicon at low temperature and atmospheric pressure

ABSTRACTIn a rapid thermal processing system working at a total pressure of a few Torr, we have obtained selective epitaxial growth of silicon at temperatures as low as 650°C. When using SiH2Cl2 (DCS) as the reactive gas, no addition of HCl is needed. Nevertheless, using SiH4 below 950°C a small amount of HCl should be added.Some kinetic aspects of the two systems, DCS/HCI/H2 and SiH4/HCl/H2, are presented and discussed. For the DCS system, we show that the rate-limiting reactions are slightly different from those commonly accepted in the literature, where the results are from systems working at atmospheric pressure or in the 20-100 Torr range.Our model is based on the main decomposition of DCS, SiH2Cl→SiHCl + HCl, instead of the widely accepted reaction SiH2Cl2→SiCl2 + H2. This is the main reason why no extra HCl is required in the DCS/H2 system to obtain full selectivity from above 1000°C down to 650°C.

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The Effect of Ge Segregation on Oxidation of Si

MRS Proceedings ◽

10.1557/proc-105-277 ◽

1987 ◽

Vol 105 ◽

Cited By ~ 8

Author(s):

E. C. Frey ◽

N. R. Parikh ◽

M. L. Swanson ◽

M. Z. Numan ◽

W. K. Chu

Keyword(s):

High Pressure ◽

Low Temperature ◽

Epitaxial Layer ◽

Atmospheric Pressure ◽

Oxidation Rate ◽

Oxidation Temperature ◽

Pressure Oxidation ◽

Enhanced Oxidation ◽

High Pressure Oxidation

AbstractWe have studied oxidation of various Si samples including: Ge implanted Si, CVD and MBE grown Si(0.4–4% Ge) alloys, and MBE grown Si-Si(Ge) superlattices. The samples were oxidized in pyrogenic steam (800–1000°C, atmospheric pressure) and at low temperature and high pressure (740°C, 205 atm of dry O2). The oxidized samples were analyzed with RBS/channeling and ellipsometry.An enhanced oxidation rate was seen for all Ge doped samples, compared with rates for pure Si. The magnitude of the enhancement increased with decreasing oxidation temperature. For steam oxidations the Ge was segregated from the oxide and formed an epitaxial layer at the Si-SiO2 interface; the quality of the epitaxy was highest for the highest oxidation temperatures. For high pressure oxidation the Ge was trapped in the oxide and the greatest enhancement in oxidation rate (>100%) was observed.

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CO2 hydrogenation into CH4 over Ni–Fe catalysts

Functional Materials Letters ◽

10.1142/s1793604718500571 ◽

2018 ◽

Vol 11 (03) ◽

pp. 1850057 ◽

Cited By ~ 8

Author(s):

Reza Meshkini Far ◽

Olena V. Ischenko ◽

Alla G. Dyachenko ◽

Oleksandr Bieda ◽

Snezhana V. Gaidai ◽

...

Keyword(s):

Low Temperature ◽

Synergistic Effect ◽

Atmospheric Pressure ◽

High Efficiency ◽

Co2 Hydrogenation ◽

Hydrogenation Catalysts ◽

Fe Catalysts ◽

First Time ◽

Supported Ni ◽

Hydrogenation Of Co

Here, we report, for the first time, on the catalytic hydrogenation of CO2 to methane at atmospheric pressure. For the preparation of hydrogenation catalysts based on Ni and Fe metals, a convenient method is developed. According to this method, low-temperature reduction of the co-precipitated Ni and Fe oxides with hydrogen gives the effective and selective bimetallic Ni[Formula: see text]Fe[Formula: see text], Ni[Formula: see text]Fe[Formula: see text] and Ni[Formula: see text]Fe[Formula: see text] catalysts. At the temperature range of 300–400[Formula: see text]C, they exhibit a high efficiency of CH4 production with respect to monometallic Ni and Fe catalysts. The results imply a synergistic effect between Ni and Fe which caused the superior activity of the Ni[Formula: see text]Fe[Formula: see text] catalyst conversing [Formula: see text]% of CO2 into CH4 at 350[Formula: see text]C. To adapt the Ni–Fe catalysts in the industry, the effect of two different carriers on the efficiency of the alumina-supported Ni[Formula: see text]Fe[Formula: see text] catalyst was investigated. It is found that the Ni[Formula: see text]Fe[Formula: see text]/[Formula: see text]-Al2O3 catalyst effectively conversed CO2 giving 100% methane yield already at 275[Formula: see text]C.

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