NOVEL CARBON-DOPED P-CHANNEL GAAS METAL-SEMICONDUCTOR FIELD-EFFECT TRANSISTOR GROWN BY METALORGANIC MOLECULAR-BEAM EPITAXY

A high performance GaAs p-metal-semiconductor field-effect transistor (MESFET) using carbon as the p-dopant is demonstrated. The channel and contact layers were grown by metalorganic molecular beam epitaxy (MOMBE). The cap contact layer was highly doped with carbon (5 x 10(20) cm-3) in order to minimize the parasitic resistance in the FET structure. The sheet resistivity and transfer resistance of the contacts were 220 OMEGA/open-square-box and 0.2 OMEGA-mm, respectively. These are comparable to values achieved on n-type GaAs. The room temperature extrinsic transconductance and K-factor values were 50 mS/mm and 165 mS/V.mm with 1-mu-m gate length and 3.5-mu-m source-to-drain spacings. These are the highest room temperature values ever demonstrated for p-GaAs MESFET.