Bandgap and strain engineered si-ge-c vertical and planar mosfets
Sanjay Banerjee (

)
Electrical and Computer Engineering, MER 1.606B/R9900, University of Texas,
Austin, TX 78712, USA
We will discuss the application of Si-Ge-C binary/ ternary alloy
pseudomorphic strained layers (with dilute C levels of ~1%) grown by
low-temperature ultra high vacuum chemical vapor deposition (UHVCVD) in novel,
high-carrier-mobility strained vertical and planar P and N-channel MOSFETs.
The main motivation for grafting Ge and C onto Si technology is that the use
of such heterostructures enables one to do somewhat independent bandstructure
and strain engineering (both compressive with Si-Ge and tensile with Si-C) to
achieve enhanced transport properties.
For example, we will show how bandgap engineering in novel vertical P-MOSFETs
can be used to suppress the short channel effects, floating body effects, and
improve the drive current. SiGe source/Si channel heterobarriers are used to
suppress leakage effects in sub-100nm devices, while a SiGe/Si compressively
strained, high mobility cap layer is used to provide higher drive current. The
use of high-K gate dielectrics (HfO2 and ZrO2) on Si-Ge planar MOSFETs will be
discussed, and the challenges and opportunities will be pointed out. Finally,
the use of Si-Ge-C and high-K dielectrics in novel flash memory MOS devices
with Si-Ge-C self-assembled quantum dot floating gates will be discussed. We
will show that such approaches are promising in terms of low voltage/ low
power programming of these cells, along with improved non-volatility.