Low Pressure Chemical Vapor Deposition of Si1 − xGex Films Using Si2 H 6 and GeH4 Source Gases

Abstract

We have investigated the deposition behavior of (x ⩽ 0.31) films using and source gases in low pressure chemical vapor deposition. The deposition temperature and pressure were varied from 400 to 500°C and from 0.5 to 1 Torr, respectively. We identified that the germanium content in the film slightly increased with pressure, while it did not change with temperature at a fixed flow rate of two source gases. The deposition rate was enhanced as the germanium incorporation in the film was increased, and the activation energy obtained from the Arrhenius plot of deposition rate decreased from 1.5 eV for Si to 1 eV for . Both these results were attributed to lowering the activation energy of hydrogen desorption from the growing film surface. The transition temperature from amorphous to polycrystalline during the deposition was about 475°C for the alloy film, and the average grain size of this film deposited at 500°C was measured as approximately 60 nm.