GaN-based MIS-HEMTs with Al₂O₃ dielectric deposited by low-cost and environmental-friendly mist-CVD technique

Abstract

We report on the fabrication and characterization of AlGaN/GaN metal-insulator-semiconductor (MIS) capacitors and high-electron-mobility transistors (MIS-HEMTs) using a 5 nm thick Al2O3 dielectric deposited by cost-effective and environmental-friendly mist chemical vapor deposition (mist-CVD) technique. Practically hysteresis-free capacitance–voltage profiles were obtained from the fabricated two-terminal MIS-capacitors indicating high quality of the mist-Al2O3/AlGaN interface. Compared with reference Schottky-gate HEMTs, mist MIS-HEMTs exhibited much improved performance including higher drain current on-to-off ratio, much lower gate leakage current in both forward and reverse directions and lower subthreshold swing. These results demonstrate the potential and viability of non-vacuum mist-CVD Al2O3 in the development of high-performance GaN-based MIS-HEMTs.

Comparison of the Electrical Performance of AlN and HfO₂Passivation Layer in AlGaN/GaN HEMT

“…Passivation layer plays a critical role in device performance and reliability which is known to have the ability to alter known defects such as reducing current leakage [1] [2] and improving breakdown voltage [3] [4]. It is not limited to the properties of a narrow bandgap, high dielectric constant and high band off-set in order to improve AlGaN/GaN HEMT device performance.…”

Evaluation of the border traps in LPCVD Si3N4/GaN/AlGaN/GaN MIS structure with long time constant using quasi-static capacitance voltage method

“…In-situ and ex-situ gate dielectrics, such as Si 3 N 4 , SiO 2 , Al 2 O 3 , have been grown with chemical vapor deposition (CVD) or atomic layer deposition for GaN MISHEMT. [6][7][8] It is generally recognized that the interface trap density is much higher in MOS or MIS structures with III-V channel than that in SiO 2 /Si MOS structure. Besides the interface traps, there is another type of trap, named border trap with long time constant, existing in such structure.…”

Low thermal budget V/Al/Mo/Au ohmic contacts for improved performance of AlGaN/GaN MIS-HEMTs

“…The Vbased MIS-capacitor, however, displayed a pronounced "spill-over" phenomenon as suggested by the sudden increase of capacitance at sufficiently high applied V G , indicating the spill-over of electrons from the 2DEG channel to Al 2 O 3 /AlGaN interface. 5,25) This prominent "spill-over" in V-based MIS-capacitors is another manifestation of improved Al 2 O 3 /AlGaN interfacial quality in these structures.…”