Polycrystalline Si1-xGex (poly Si-Ge) was explored as a process compatible alternative gate material for PMOS transistors at RIT. This material has been previously shown to exhibit several favorable characteristics when used as a gate material for PMOS transistors. Benefits include the ability to engineer the workfunction, improved dopant activation for reduced gate depletion effects, and reduced boron encroachment. A process by which poly Si-Ge could be integrated as a gate material into the RIT submicron CMOS process was developed by alternating polycrystalline silicon deposition by LPCVD and the application of germanium by PVD. The effects on physical composition of the gate stack and an attempt to understand germanium diffusion through polysilicon was also explored.
Mattioli, Michael C.
"Development of a Polycrystalline Si1-xGex Gate Material by LPCVD/PVD,"
Journal of the Microelectronic Engineering Conference: Vol. 13
, Article 15.
Available at: http://scholarworks.rit.edu/ritamec/vol13/iss1/15