Pulsed metal organic chemical vapor deposition of nearly latticed-matched InAlN/GaN/InAlN/GaN double-channel high electron mobility transistors

Abstract

High quality, nearly lattice-matched InAlN/GaN/InAlN/GaN double-channel heterostructures were grown on sapphire by pulsed-metal-organic-chemical-vapor-deposition (PMOCVD). High electron mobility of 1414 cm 2 /Vs was achieved along with a two-dimensional-electron-gas density of 2.55 Â 10 13 cm À2. We attribute it to the high quality PMOCVD-grown InAlN barriers and, additionally, to the novel GaN layer growth between two InAlN barriers, which consists of a thin GaN spacer to prevent indium-redistribution and indium-cluster formation during the subsequent growth and a relatively thick GaN channel to enhance electron mobility. High-electron-mobility-transistors fabricated on these heterostructures with 0.8-lm-length gate exhibit a maximum drain current of 906 mA/mm and a transconductance of 186 mS/mm.

Trap states in InAlN/AlN/GaN-based double-channel high electron mobility transistors

“…We attribute the much lower trap states to a 2 nm LT-GaN spacer deposited on the bottom InAlN/AlN barrier, capable of avoiding the risk of indium cluster formation and indium redistribution during the high temperature GaN channel growth. 9 Contrarily, no cap was grown on the top InAlN barrier, enabling the vulnerability to subsequent device processes, especially high temperature annealing (830 C here).…”

“…9 The epitaxial structure is composed of, from the substrate up, a 1.6 lm GaN buffer layer, a 1 nm AlN interlayer, a 12 nm In 0.17 Al 0.83 N bottom barrier layer, a 20 nm GaN layer, a 1 nm AlN interlayer, and a 12 nm In 0.17 Al 0.83 N top barrier layer. While a low reverse leakage current on the order of 1 and 40 lA/mm at gate-drain voltage of V GD ¼ À10 and À20 V, respectively, was achieved, 10 it still exhibited three orders of magnitude higher than that of AlGaN barrier devices fabricated in our laboratory, which suggested the possible existence of relatively higher trap or/and dislocations density.…”

Fabrication and characterization of InAlN/GaN-based double-channel high electron mobility transistors for electronic applications

“…A prerequisite for a monolithic approach to the realization of such devices is high quality epitaxial DC InAlN/GaN heterostructures. Fortunately, our group has successfully overcome the growth impediment by using pulsed metal organic chemical vapor deposition (PMOCVD), [13][14][15][16] an inspiring method and facilitating the InAlN material-related applications. Here, we report on a detailed fabrication and characterization of HEMTs made of those DC InAlN/GaN heterostructures for electronic applications like frequency multipliers and mixers.…”

Investigation of TMIn pulse duration effect on the properties of InAlN/GaN heterostructures grown on sapphire by pulsed metal organic chemical vapor deposition

“…In previous work, we have successfully grown high quality nearly lattice-matched InAlN/GaN heterostructures by pulsed MOCVD (PMOCVD) and demonstrated the potential advantages of PMOCVD [8][9][10]. Fig.…”