LT-GAAS WITH HIGH BREAKDOWN STRENGTH AT LOW-TEMPERATURE FOR POWER MISFET APPLICATIONS

Low temperature grown GaAs has been fabricated containing a limited am ount of excess arsenic. The material has a low conductivity in the ord er of 100K Ohm cm, due to hopping in a deep donor band. This sigma-LT- GaAs was grown reproducibly by using the lattice mismatch as the prima ry parameter for substrate temperature calibration. Breakdown fields, in the order of 100kV/cm, are observed for planar structures and incre ased at low measurement emperatures. Low hopping conductivity and high breakdown field are also observed in the lossy dielectric metal-insul ator-semiconductor field-effect transistor device using sigma-LT-GaAs as a surface layer. The record radio frequency power density of 4.0W/m m at 77K is extracted from the de output characteristics.