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Metal–oxide–semiconductor high‐electron‐mobility transistors were demonstrated on AlGaN/GaN with electron beam (EB) evaporated ZrO2. The composition of the EB deposited ZrO2 thin films was confirmed using X‐ray photoelectron spectroscopy (XPS). The fabricated ZrO2‐based MOSHEMTs exhibited high positive gate voltage of operation up to +7 V with low gate leakage current. For a comparison, conventional high‐electron‐mobility transistors (HEMTs) were also fabricated with identical device dimensions. The maximum drain current densities of 1168 and 538 mA/mm were observed on MOSHEMTs and HEMTs, respectively. Low gate leakage current density of four orders of magnitude was observed on ZrO2‐based MOSHEMTs when compared with the conventional HEMTs. The observation of high forward on‐voltage with low gate leakage current density and high positive operational voltage reveals the importance of ZrO2 dielectric films for MOSHEMT devices. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

AlGaN is an important material for ultra‐violet light emitters, photo detectors and high breakdown voltage switching devices. In this work, crack‐free AlxGa1‐xN (5% < x < 55%) layers up to 1.5 μm have been grown on 4 inch Si(111) using an AlN/AlyGa1‐yN (y > 70%) template. The structural quality of AlGaN layers is comparable to that of GaN layers grown on silicon(111). For Al0.16Ga0.84N, the FWHM of HR‐XRD (0002) and (‐1102) ω‐scan is around 650 arc sec and 1200 arc sec respectively. Based on this high quality AlGaN buffer, a double heterostructure (DH) FET was demonstrated. The sheet resistance of DH‐FET is 274 ± 4.7 Ω/□ and the uniformity value of 1.7% is also excellent. Some of the wafers have been processed. Devices with a gate length of 2 μm showed current density of 500 mA/mm and transconductance of more than 200 mS/mm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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