UNIFORMITY OF THE HIGH-ELECTRON-MOBILITY TRANSISTORS AND RESONANT-TUNNELING DIODES INTEGRATED ON AN INP SUBSTRATE USING AN EPITAXIAL STRUCTURE GROWN BY MOLECULAR-BEAM EPITAXY AND METALORGANIC CHEMICAL-VAPOR-DEPOSITION

We integrated InAlAs/InGaAs high electron mobility transistors (HEMTs) and InGaAs/AlAs/InAs resonant tunneling diodes (RTDs) on an InP subst rate. To obtain uniform threshold voltages, we inserted an InP etch-st op layer into the InAlAs barrier layer of the HEMT. We used metalorgan ic chemical vapor deposition (MOCVD) to grow the HEMT layers and molec ular beam epitaxy (MBE) to grow the RTD layers. This is because InP la yers can be easily grown using MOCVD, but MBE is a superior technique for growing highly strained resonant tunneling structures consisting o f AlAs/InGaAs/InAs. The average threshold voltage and transconductance of HEMTs with 0.7-mu m-long gates fabricated on a 2 inch wafer were - 0.44 V and 843 mS/mm, respectively, and the standard deviations of the se values were only 30 mV and 15.7 mS/mm, respectively. Despite the re growth procedure used to fabricate the RTDs, they had good current-vol tage (I-V) characteristics and the standard deviation of the peak curr ent was only 3%.