Rapid thermal chemical vapor deposition of in situ boron-doped polycrystalline silicon-germanium films on silicon dioxide for complimentary-metal-oxide-semiconductor applications

摘要

In situ boron-doped polycrystalline Si↓(1-x)Ge↓(x) (x>0.4) films have been formed on the thermally grown oxides in a rapid thermal chemical vapor deposition processor using SiH↓(4)-GeH↓(4)-B↓(2)H↓(6)-H↓(2) gas system. Our results showed that in situ boron-doped Si↓(1-x)Ge↓(x) films can be directly deposited on the oxide surface, in contrast to the rapid thermal deposition of undoped silicon-germanium (Si↓(1-x)Ge↓(x) films on oxides which is a partially selective process and requires a thin silicon film pre-deposition to form a continuous film. For the in situ boron-doped Si↓(1-x)Ge↓(x) films, we observed that with the increase of the germane percentage in the gas source, the Ge content and the deposition rate of the film are increased, while its resistivity is decreased down to 0.66 mΩ cm for a Ge content of 73. Capacitance-voltage characteristics of p-type metal-oxide-semiconductor capacitors with p↑(+)-Si↓(1-x)Ge↓(x) gates showed negligible polydepletion effect for a 75# gate oxide, indicating that a high doping level of boron at the poly-Si↓(1-x)Ge↓(x)/oxide interface was achieved. # 1997 American Institute of Physics. S0003-6951 (97)04349-0