InAlAs/InGaAs metamorphic HEMT and MOS-HEMT with regrown Source/Drain by MOCVD

As scaling technologies are being stretched harder and harder in the roadmap of Si based CMOS, III-V compounds have become competitive alternative channel materials for the next generation high speed and low power transistors. Among various device structures, InGaAs HEMT has been intensively researched in the past few years because of its excellent carrier transport properties. However, conventional HEMT structures requiring recessed gate technology may be difficult for digital VLSI applications due to their large footprint and higher parasitic capacitances. Moreover, the gate recess process raises serious concerns in threshold voltage uniformity caused by variations in recess etching depth. Selective Source/Drain (S/D) regrowth, which has been implemented in advanced Si pMOSFET, is an easier and scalable approach to facilitate ohmic contact in HEMT structures, with the benefits of eliminating reliability issues related to gate recess and parasitic reduction. In this paper, we describe the process and preliminary device results of metamorphic HEMTs (mHEMTs) and MOS-HEMTs on GaAs substrates with highly doped Ino.53Gao.47As S/D by selective regrowth using MOCVD.