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

Abstract

We integrated InAlAs/InGaAs high electron mobility transistors (HEMTs) and InGaAs/AlAs/InAs resonant tunneling diodes (RTDs) on an InP substrate. To obtain uniform threshold voltages, we inserted an InP etch-stop layer into the InAlAs barrier layer of the HEMT. We used metalorganic chemical vapor deposition (MOCVD) to grow the HEMT layers and molecular beam epitaxy (MBE) to grow the RTD layers. This is because InP layers can be easily grown using MOCVD, but MBE is a superior technique for growing highly strained resonant tunneling structures consisting of AlAs/InGaAs/InAs. The average threshold voltage and transconductance of HEMTs with 0.7-µm-long gates fabricated on a 2 inch wafer were -0.44 V and 843 mS/mm, respectively, and the standard deviations of these values were only 30 mV and 15.7 mS/mm, respectively. Despite the regrowth procedure used to fabricate the RTDs, they had good current–voltage (I–V) characteristics and the standard deviation of the peak current was only 3%.