Anomalous capacitance–voltage characteristics of Pt–AlGaN/GaN Schottky diodes exposed to hydrogen

Abstract

We have investigated the interaction of hydrogen with Pt‐AlGaN/GaN Schottky barrier diodes (SBDs) using a low‐frequency capacitance‐voltage (C‐V) technique. At a frequency of 1kHz, the C‐V curve in hydrogen shifts toward negative bias values as compared with that in nitrogen. As the frequency decreases from 1kHz to 1Hz, the capacitance in hydrogen significantly increases and the fluctuations of the capacitance are observed. These C‐V characteristics are quite anomalous and have not been reported yet, suggesting the formation of interfacial polarization which could be attributable to hydrogen‐related dipoles. The fluctuation of the capacitance may be related to the alignment of the dipoles. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Influence of deep levels on capacitance-voltage characteristics of AlGaN/GaN heterostructures

“…Decreasing capacitance toward forward voltage was observed also by Si et al, 18 which is also probably caused by forming deep levels in the heterostructure by fluorine plasma treatment. Similar capacitance behaviorÀcapacitance peak in the left part of expected capacitance plateau has been observed by Kordoš et al 19 and Irokawa et al 20 But in those experiments, the capacitance plateau was still present in very low negative or even positive voltage. Our results are a bit different from these two.…”

Influence of AlN and GaN Pulse Ratios in Thermal Atomic Layer Deposited AlGaN on the Electrical Properties of AlGaN/GaN Schottky Diodes

“…Meanwhile, hydrogen exposure at room temperature in Pt/SiO 2 /GaN diodes changed the conduction mechanisms from Fowler-Nordheim (FN) tunneling to PF emission and the C-V curve shifted toward negative bias values [52]. The significant increase in the capacitance at a low frequency in the Pt/AlGaN/GaN Schottky diodes was observed after hydrogen exposure, which was associated with hydrogen-related dipoles [53]. Hydrogen treatment on AlGaN/GaN HEMT was found to reduce the trap density by about one order of magnitude [54].…”

Low- and high-frequency capacitance of aluminum gallium nitride/gallium nitride heterostructures with interface traps

“…It was assumed that the effect was connected with interfacial polarization attributable to hydrogen-related dipoles created in the structure. Observed peak in the capacitance has been named as anomalous capacitance [13]. A similar shape of the C-V curves was measured also by Liu et al [14] for metal semiconductor and also for MOS capacitors.…”

“…In the voltage region where the traps change their charge state, the resulting capacitance may be larger than the high frequency capacitance. Such curves measured on experimental samples have been published in the literature for frequencies 10 kHz [12] and even lower [13] for Schottky barrier structures exposed to hydrogen. It was assumed that the effect was connected with interfacial polarization attributable to hydrogen-related dipoles created in the structure.…”