David B. Salzman

Properties of InAs metal-oxide-semiconductor structures with atomic-layer-deposited Al2O3 Dielectric

InAs is very attractive as a channel material for high-speed metal-oxide-semiconductor (MOS) field-effect transistors due to its very high electron mobility and saturation velocity. We investigated the processing conditions and the interface properties of an InAs metal-oxide-semiconductor structure with Al2O3 dielectric deposited by atomic-layer deposition. The MOS capacitor I-V and C-V characteristics were studied and discussed. Simple field-effect transistors fabricated on an InAs bulk material without source/drain implantation were measured and analyzed.

Molecular beam epitaxy growth of InAs and In0.8Ga0.2As channel materials on GaAs substrate for metal oxide semiconductor field effect transistor applications

InAs and high indium concentration InGaAs have very high electron mobilities and saturation velocities. Using them as the metal oxide semiconductor field effect transistor (MOSFET) channel materials is a very promising way to keep improving the integrated circuit chip performance beyond Moore’s law. One major obstacle is the growth of these high mobility channel materials on lattice-mismatched substratcs. In this work, we studied the molecular beam epitaxy growth of InAs, In0.8Al0.2As, and In0.8Ga0.2As on lattice-mismatched GaAs substrate using a thin indium-rich InAs wetting layer. Reflection high energy electron diffraction and atomic force microscopy were used to optimize the growth conditions. A surface roughness of ∼0.5nm rms was obtained for InAs layers. A new MOSFET structure with In0.8Ga0.2As channel and In0.8Al0.2As buffer layer was also demonstrated. High mobility depletion mode MOSFET characteristics were demonstrated.