Abstract
A four-terminal MESFET-like GaAs multiple-function transistor (MFT) with a buried silicon-doping quantum well has been demonstrated by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The vertical GaAs negative resistance field-effect transistor (NERFET) based on real-space transfer exhibits a high current driving capability, a high peak-to-valley ratio up to 2160, and a high transconductance of 2.1 S/mm at room temperature. In addition, we carried out an ohmic recess to form nonallyed contacts which are electrically isolated from ohmic electrodes. By virtue of nonalloyed ohmic contacts, a planar metal-semiconductor field-effect transistor (MESFET) has been fabricated on the same wafer successfully. The MESFET with a 2×100 µm2 gate exhibits a maximum extrinsic transconductance of 70 mS/mm, a saturation current density of 172 mA/mm, and a Schottky breakdown voltage larger than 15 V at room temperature.