AsH3 Flow Rate Research Articles

In-Situ Heavy as Doping in Si Selective Epitaxial Growth

ABSTRACTRole of in-situ heavy As doping in Si selective growth is studied using the SiH2Cl2/H2/HCl/AsH3 gas system. By increasing AsH3 flow rate, the growth rate decreases in proportion to In (AsH3 flow rate). This result is explained well using a Frumkin-Temkin adsorption model. The As concentrations in grown films depend on surface orientation. Moreover, the maximum As concentration is about ten times lower than the solubility limit at a given temperature. These results are able to be explained qualitatively, if equilibrium concentrations of impurities at the Si(100), the Si(111), and the bulk are assumed to be different from one another, and that the concentration at the surface is frozen in the grown film.

AlxGa1-xas Growth by OMVPE Using Trimethylamine Alane

ABSTRACTWe have investigated the growth of AlxGal-xAs (0.1 ≤ x ≤ 1) by organometallic vapor phase epitaxy using trimethylamine alane (TMAA1) as the aluminum precursor. A low pressure (30 Torr) reactor was used with hydrogen as the carrier gas. At the high gas velocities (> 1 m · s-1) employed there was no visible deposition upstream of the substrate. AIGaAs epilayers with featureless surface morphology could be obtained over the entire range of composition. The layers exhibited very strong room-temperature photoluminescence and excellent compositional uniformity (x = 0.235 ± 0.002 over a 40 mm diameter). A comparison was made between the electrical and optical characteristics of AlGaAs grown with either trimethylgallium (TMGa) or triethylgallium (TEGa). The hole concentration of the layers grown using TMGa was significantly higher than that with TEGa (e.g., 6–7 × 1017cm-3vs. 1 × 1016cm-3) for the same TMAA1 and AsH3mole fractions. High-purity AlGaAs was achieved with TMAAl and TEGa at higher AsH3flow rates.

Selective deposition of i n s i t u doped polycrystalline silicon by rapid thermal processing chemical vapor deposition

Selective polycrystalline silicon was successfully deposited and in situ doped wih arsenic for the first time by rapid thermal processing chemical vapor deposition (RTPCVD). The growth kinetics of SiH2Cl2/AsH3/H2 gas system have been studied by examining the dependence of growth rate on deposition temperature, volume percentage of SiH2Cl2, and AsH3 mole fraction. Submicron polycrystalline silicon layers with excellent selectivity and precise thickness control have been achieved with proper deposition conditions. The growth rate decreases as doping levels increase, and drastically decreases when the AsH3 mole fraction is higher. In addition, the growth rate is linearly proportional to the SiH2Cl2 flow rate for a fixed AsH3 flow rate.

Systematic studies on the effect of growth interruptions for GaInAs/InP quantum wells grown by atmospheric pressure organometallic vapor-phase epitaxy

GaInAs/InP quantum wells were grown by using atmospheric pressure organometallic vapor-phase epitaxy with and without interruptions at the interfaces. The growth schedule has a major effect on the optical properties of the quantum wells. For approximately 10-Å-thick wells, the ground-state energy as determined by 10-K photoluminescence decreases in the following order: continuous growth, an interruption at the second interface, and interruptions at both interfaces. It is demonstrated that As is effective in substituting for P atoms on the InP surface during AsH3 purge. Varying the AsH3 flow rate during growth of the GaInAs well layer significantly influences the emission energies for samples grown continuously or with an interruption at the second interface. However, the emission energies of quantum wells grown with interruptions at both interfaces are found to be independent of the AsH3 flow rate, indicating insignificant substitution of As for P in the InP barriers. An interfacial layer of InAsxP1−x may play a dominant role in determining the emission energies for quantum wells thinner than 50 Å.