Electronic properties of MBE grown GaAs homointerfaces fabricated using the As cap deposition/removal technique

High mobility NMOSFET structure with high-/spl kappa/ dielectric

“…Note that the Al Ga As barrier layer serves a number of purposes which include widening of the semiconductor surface bandgap [10] and alleviating mobility degradation caused by interface and oxide traps as well as oxide soft-polar optical phonons. Widening of the surface bandgap is in particularly important in high mobility material systems because the effective density of states in the conduction band is considerably lower compared to Si (e.g., and 2.8 cm for GaAs and Si, respectively, [13]) and interface state densities typically rise toward the conduction band edge.…”

“…The NMOSFET layer structure is designed for enhancement mode operation, i.e., an NMOSFET threshold voltage . Details about the basic concept of implant-free, high mobility MOSFETs can be found in [10], [11]. For reference purposes, a standard pseudomorphic high electron mobility transistor (PHEMT) structure in which 0741-3106/$20.00 © 2005 IEEE TABLE I TRANSPORT DATA OF GaAs NMOSFET AND PHEMT STRUCTURES the gate dielectric is replaced by a 30-nm GaAs cap layer has also been grown.…”