A study of GaN MOSFETs with atomic-layer-deposited Al₂O₃as the gate dielectric

Abstract

Accumulation-type GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) with atomic-layer-deposited Al2O3 gate dielectrics are fabricated. The device, with atomic-layer-deposited Al2O3 as the gate dielectric, presents a drain current of 260 mA/mm and a broad maximum transconductance of 34 mS/mm, which are better than those reported previously with Al2O3 as the gate dielectric. Furthermore, the device shows negligible current collapse in a wide range of bias voltages, owing to the effective passivation of the GaN surface by the Al2O3 film. The gate drain breakdown voltage is found to be about 59.5 V, and in addition the channel mobility of the n-GaN layer is about 380 cm2/Vs, which is consistent with the Hall result, and it is not degraded by atomic-layer-deposition Al2O3 growth and device fabrication.

Comparison of electrical characteristic between AlN/GaN and AlGaN/GaN heterostructure Schottky diodes

“…For many years, AlGaN/GaN heterostructure field-effect transistors (HFETs) have been the subject of intense investigation due to their importance for microwave and high temperature/high power applications. [1][2][3] Nowadays, up-to-date materials of AlN/GaN heterostructure are of great advantage for high frequency operation, since AlN offers the greatest potential as a scalable barrier material among Al x Ga 1−x N alloy compositions due to its large bandgap and polarization effects. [4,5] The best frequency ( f max / f T : 342 GHz/518 GHz) is obtained on the AlN/GaN heterostructure due to the thin barrier layer and polarization effects.…”

Effect of ultrathin GeOxinterfacial layer formed by thermal oxidation on Al2O3capped Ge

“…Afterwards, the first Al 2 O 3 deposition layer, which is the OBL shown in Fig. 1(a), was grown on the Ge substrate by ALD at 300 • C. [17] Thermal oxidation was carried out inside a rapid thermal furnace at atmospheric pressure in pure oxygen ambient at 550 OBLs and oxidation time, were investigated by X-ray photoelectron spectroscopy (XPS) measurements and spectroscopy ellipsometry.…”

GaSb p-Channel Metal-Oxide-Semiconductor Field-Effect Transistors with Ni/Pt/Au Source/Drain Ohmic Contacts

“…[5] A 10 nm Al 2 O 3 layer was then deposited at 300 ∘ C in a Beneq TFS200 ALD chamber by using trimethylaluminum (TMA) and water as the precursors with TMA being the starting pulse. [21] After a post deposition annealing (PDA) that performed at 350 ∘ C for 30 s in N 2 ambient, Ti/Au gate electrode was deposited by ebeam evaporation and patterned by a lift-off process. Then the source and drain regions were selectively implanted with a Be dose of 3 × 10 14 cm −2 at 30 keV through the 10 nm Al 2 O 3 encapsulation layer.…”