Silicon epitaxial growth accelerated by parallel Langmuir processes using SiH₂Cl₂ and SiH₃CH₃ gases

Abstract

The silicon epitaxial growth behaviour was studied as an application of the parallel-Langmuir process using SiH2Cl2 gas and SiH3CH3 gas. The SiH3CH3 gas was used for in situ producing the SiHx gas by thermal decomposition in the reactor. With the increasing gas concentration of SiH3CH3, several results were obtained, such as (i) the silicon epitaxial growth rate increased exceeding the value saturated using the SiH2Cl2, (ii) the gas phase concentrations of the chlorosilanes at the exhaust decreased, (iii) the byproduct deposition at the exhaust decreased, and (iv) the gas phase concentration of HCl at the exhaust decreased. As a conclusion, the SiHx helped consuming the SiH2Cl2 gas for producing a silicon epitaxial film with reducing the byproduct deposition. Additionally, the SiHx might produce SiH2Cl2 in the gas phase by the reaction with the HCl gas.

Boron-Silicon Film Chemical Vapor Deposition Using Boron Trichloride, Dichlorosilane and Monomethylsilane Gases

“…Boron trichloride and monomethylsilane gases.-The monomethylsilane gas was used with the boron trichloride gas at 800 °C. Similar to the previous studies, [21][22][23][24] SiH y was expected to be produced in the gas phase by the thermal decomposition of the monomethylsilane gas. The obtained deposition rate and the concentration of various elements are shown in Figs.…”

“…Taking into account the ratio of the surface site occupied by the intermediate species of BCl x and SiCl 2 , θ BClx and θ SiCl2 , respectively, the chemical reactions and their rates are assumed. 21 The dichlorosilane is chemisorbed on the vacant sites of the surface to produce the intermediate species, SiCl 2 . Next, the SiCl 2 reacts with the hydrogen to produce silicon.…”

“…Additionally, the silicon had the Si-Si bonds at 14%-20%, which were produced from any byproduct of the monomethylsilane gas, such as SiH y . [21][22][23][24] Because the SiH y has been well known to be produced by the thermal decomposition of monosilane, SiH 4 , 28 the monosilane is considered to have the same process with the boron trichloride gas.…”

“…Because the silicon deposition rate by the monomethylsilane gas at 800 °C was significantly low, [21][22][23][24] the obtained deposition rate in Fig. 6 was expected to occur by the reaction of *BCl x with the SiH y and the monomethylsilane gases following Eqs.…”

“…For this purpose, the deposition rate should be taken into account. In recent reports, [21][22][23][24] the parallel Langmuir process has been studied for increasing the surface reaction rate exceeding the highest limit determined by the Langmuir-type rate theory, which contained the reaction concept of mixed precursors by Hartman et al 25,26 In this model, a silicon hydride and hydrogen were assumed to simultaneously react with the intermediate surface species, SiCl 2 . Because this reaction effectively produces the hydrogen chloride gas to remove the chlorine atoms from the surface, the silicon deposition rate can be high even at the low temperatures.…”