Effect of annealing on gan-insulator interfaces characterized by metal-insulator-semiconductor capacitors

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…[173] Towards that end, materials such as Al 2 O 3 (itself an UWBG semiconductor in its crystalline form), SiO 2 , and Si 3 N 4 have been used in conventional AlGaN/GaN power HEMTs to limit gate leakage in normally-off, gate-recessed structures (in these structures the gate dielectric is deposited on the AlGaN barrier layer). [174] Also, Al 2 O 3 deposited on AlGaN has been shown to affect HEMT properties such as 2DEG density and mobility.…”

Highly-stable and low-state-density Al2O3/GaN interfaces using epitaxial n-GaN layers grown on free-standing GaN substrates

“…Similar frequency dispersions in C-V characteristics were reported for SiO 2 /GaN and Al 2 O 3 /GaN structures. 7,8,15 In addition, bump-like C-V curves at low frequencies indicate the existence of a discrete level with relatively high density at the GaN surface. On the other hand, excellent C-V characteristics with negligible frequency dispersion were observed in the MOS sample after the annealing in air at 300 C for 3 h under a reverse bias voltage of À10 V, as shown in Fig.…”

“…For high temperature C-V measurements, it is expected that deeper interface states can respond both to bias sweeping and ac signal modulation, causing changes in C-V characteristics compared with those measured at RT. In fact, Matocha et al, 8,23 Ooyama et al, 24 and Long et al 15 reported significant stretch-out of C-V curves, bump-like C-V behavior, and enhanced frequency dispersion for SiO 2 /GaN and Al 2 O 3 /GaN structures at measurement temperatures from 175 to 300 C. Such unstable C-V behavior at high temperatures indicates that relatively high-density interface states can cause operation instability in GaN-based MOSFETs. In our reverse-bias annealed sample, however, the high-temperature C-V behavior remained almost unchanged, as compared with the RT C-V curves shown in Fig.…”

Heteroepitaxial growth of ε-Ga2O3 thin films on cubic (111) MgO and (111) yttria-stablized zirconia substrates by mist chemical vapor deposition

“…Among wide-bandgap materials, GaN, SiC, ZnO, and AlN are widely used in blue and UV light-emitting diodes, 1,2) transparent conductive thin films, 3) thin-film transistors for liquid crystal displays, 4) Schottky barrier diodes, 5) metal-oxide-semiconductor field-effect transistors (MOSFETs) 6) for power devices, and high-mobility electron transistors for high-frequency devices. 7) These materials show the same hexagonal crystal structure with the space group P6 3 mc.…”