Improvements of electrical and thermal characteristics for AlGaN/GaN HEMT grown by metal-organic chemical vapor deposition on silicon-on-insulator (SOI) substrate

Abstract

AlGaN/GaN high electron mobility transistors (HEMTs) heterostructures are grown by metal-organic chemical vapor deposition (MOCVD) on silicon-on-insulator (SOI) substrate and high resistive (HR-Si) simultaneously to investigate the influence of substrate types on electrical and thermal characteristics. The AlGaN/GaN HEMT epitaxial structure grown on SOI achieved high electron mobility (1900±19 cm2/V·s) and high two-dimensional electron gas (2DEG) carrier concentration (9.1±0.1×1012/cm2). The GaN HEMT metal-insulator-semiconductor gate (MIS-HEMT) device fabricated on the structure grown on the SOI substrate exhibits higher saturation current and improved buffer breakdown voltage compared with devices fabricated on high-resistivity silicon (HR-Si) substrate. In particular, SOI substrate helps to improve the thermal-sensitive strain of the GaN-based heterostructure and reduced defect density in the epitaxy, thereby improve the temperature-dependent on-resistance (RON) and the dynamic RON of the device.

Improved Off-State Leakage Current and Cutoff Frequency for AlGaN/GaN HEMT by Using Silicon-on-Insulator

“…The GaN film grown on SOI substrates show a 0.24 GPa reduction in stress as compared to HR-Si due to the thinner silicon active layer over the softer SiO 2 interlayer of the SOI template, attributing to the reduction of the impact on wafer bowing and stress in GaN epilayer. 16,17 This stress relief contributes to the improvement of mobility and carrier concentration of the AlGaN/ GaN hetero-structure, 11 therefore improving the device performance fabricated on SOI substrate.…”

“…19 The remarkably low gate leakage current to 10 −7 (A mm −1 ) on SOI substrate can be contributed by the robustness of AlGaN/GaN HEMT heterostructure grown on the thin silicon active layer, such as the low vertical leakage current through the substrate 20 as well as the low lateral leakage current at AlN/Si interface as a result of the reduction of inversion charges in parasitic channel formed at AlN/Si interface owing to lower AlN tensile stress for being grown on SOI substrate. 11 A very high aspect ratio and low off-state leakage current are achieved for the planar device.…”

“…Attention was also extended to SOI substrates for their low parasitic capacitance and high speed 9 to develop GaN HEMT devices with AlGaN/GaN, 10,11 InAlN/AlN/GaN heterostructures 12 and enhancement-mode p-GaN HEMTs. 13 The GaN grown on SOI showed remarkably improved GaN stress, leakage current, and breakdown voltage compared to the traditional silicon substrate.…”

“…In addition, the advantages in dynamic-on resistance and thermal characteristics of MISHEMT devices fabricated on SOI substrate have been reported. 11 In this study, the effect of SOI substrate on off-state leakage current and cutoff frequency for AlGaN/GaN HEMT grown by metal-organic chemical vapor deposition (MOCVD) is investigated. In addition, the effect of SOI substrate on GaN stress, device knee voltage and insertion loss are also studied.…”

Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

“…Gallium nitride (GaN) based high electron mobility transistors (HEMTs) are promising for fabricating high-frequency * Author to whom any correspondence should be addressed. and high-power electronic devices due to their outstanding physical properties of a large band gap, high carrier density, superior electron mobility and high electric field saturation velocity [1][2][3]. Silicon substrates are used to grow epitaxial layers comprised of III-nitride materials to take the advantages of lower substrate cost and scaling flexibility on substrate size [4][5][6], compared with the expensive SiC substrates which are restricted to 150 mm in diameter [7].…”