Charge trapping and interface characteristics in normally-off Al2O3/GaN-MOSFETs

Impact of gamma-ray irradiation on capacitance–voltage characteristics of Al2O3/GaN MOS diodes with and without post-metallization annealing

“…Al 2 O 3 is considered to be an appropriate dielectric material for GaN since it has a high dielectric constant and large bandgap. [19][20][21] We have reported that post-metallization annealing (PMA) is very effective for improving the properties of Al 2 O 3 /GaN MOS fabricated by atomic layer deposition (ALD), i.e. reduction of the interface state density and suppression of hysteresis in the capacitance-voltage (C-V ) characteristics were realized by the PMA.…”

Investigation of interface properties of h-BN and AlN on AlGaN/GaN heterostructures

“…The trap time constants are only used in the extraction of the trap state energies. A similar range of AlN interface state time constants have also been reported elsewhere[8,11]. The trap state energy was estimated using the expression[16].…”

“…Two distinct interface trapping regions were observed namely fast and slow traps. The fast interface traps had Dit as low as 6.7×10 11 cm -2 eV -1 while the slow interface traps Dit were as low as 6.8×10 11 The 400 °C annealed MISHEMT exhibited an increase of 15% in maximum extrinsic transconductance (gmmax) and an order of magnitude reduction in reverse gate leakage, while maintaining high suppression (93-95%) of current collapse. The reduction of gate leakage current is attributed to the reduction of fast (13%) and slow (25%) interface states after post gate annealing at 400 °C.…”

“…While current devices are yet to reach the theoretical limit of GaN, significant advancements have been made over the years. Y. Uemoto et al have managed to fabricate devices with a Vbr of 10400 V (Ron ~186 mΩ.cm 2 ) using poly-AlN passivation, field plates and deep via-holes through sapphire [7] [10], Al2O3 [11], [12], HfO2 [13] or ZrO2 [14] have been used as both a passivation layer and gate dielectrics.…”

“…[133]- [136] However, some of the major limiting factors that conventional GaN HEMTs with Schottky metal gates suffer from are a high gate leakage current, self-heating, and current collapse. [9] To help solve these issues, various gate dielectrics such as SiN [10], Al2O3 [11], [12], HfO2 [13] or ZrO2 [14] have been used as both a passivation layer and gate dielectrics. However, while these materials help with solving the current collapse and gate leakage issues, their thermal conductivities are too low to help improve the self-heating issue faced by GaN based devices.…”