Improved operation stability of Al₂O₃/AlGaN/GaN MOS high-electron-mobility transistors grown on GaN substrates

Abstract

This paper presents electrical characterization of Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (HEMTs) grown on GaN substrates. The postmetallization annealing (PMA) at 300 °C achieved effective reduction of electronic states at the Al2O3/AlGaN interface, leading to improved gate controllability and current linearity of the MOS HEMTs. The MOS HEMT with PMA showed a subthreshold slope of 68 mV dec−1. In addition, excellent operation stability of the MOS HEMT was observed at high temperatures. Even at 150 °C, the HEMT showed low leakage current of 1.5 × 10−9 A mm−1 and a threshold voltage drift of only 0.25 V from its room temperature value.

Surface‐Oxide‐Controlled InAlGaN/GaN High‐Electron‐Mobility Transistors Using Al2O3‐Based Insulated‐Gate Structures with H2O Vapor Pretreatment

“…[20] Thus, the atomic-layer-deposited (ALD) Al 2 O 3 is desirable for high-frequency GaN MIS-HEMTs. [21][22][23][24][25][26][27][28] However, InAl(Ga)N/GaN MIS-HEMTs using ALD-Al 2 O 3 suffer from unexpected issues such as a lower drain current than the expected value, a steep decrease in g m when considering the forward gate bias, and severe current collapse, which is a temporary decrease in the drain current under high-power operation. The oxides on the surface of In-based barrier layers (surface-oxide) comprise Al 2 O 3 and indium oxide (In 2 O 3 ).…”

Low Subthreshold Slope AlGaN/GaN MOS-HEMT with Spike-Annealed HfO2 Gate Dielectric

“…Along with the vast improvement of material quality of nitrides, there have been significant improvements in device design to enhance the performance and reliability of HEMTs throughout the years [4,5]. To reduce the gate leakage and drain current collapse, for example, MOS-HEMTs have been developed with various high-k dielectrics such as Al 2 O 3 , Y 2 O 3 , and HfO 2 [6][7][8]. HfO 2 is a very promising gate dielectric for HEMTs due to its large bandgap (5.3-5.8 eV) and high dielectric constant (20)(21)(22)(23)(24)(25).…”

Charging Effect by Fluorine-Treatment and Recess Gate for Enhancement-Mode on AlGaN/GaN High Electron Mobility Transistors

“…AlGaN/GaN high electron mobility transistors (HEMTs) have recently demonstrated to be excellent devices for high-frequency and high-power electronics, thanks to the high breakdown voltage [1] and the low on-state resistance [2] and gate leakage [3]. The AlGaN/GaN HEMTs show normally on operation, since the two-dimensional electron gas (2DEG) channel is generated by the spontaneous and piezoelectric polarization at the AlGaN/GaN hetero-interface [4].…”