Structural and electrical sensitivity at several temperatures with hydrogen sensor of Ni/AlGaN Schottky diode

Abstract

The characteristics of Ni Schottky diodes on AlGaN contact the Al mole fraction up to in pure nitrogen and 2% hydrogen in nitrogen ambient are studied. High temperature stability of Ni diode on AlGaN was achieved by long term annealing at 450C at 1min. The diode I-V response from (50-450C) has been characterized, revealing the diodes ability to detect 2% hydrogen in nitrogen ambient at 100C up to 450C and pure nitrogen from 150C up to 450C. For the samples without annealing under gas of 2% hydrogen in nitrogen ambient, the ideality factor decreases from 1.77 to 1.50, and series resistance decreases from 213  to 126, and the barrier height increases from 1.00 to 1.18 eV with increasing temperature. For the Schottky contacts annealed in nitrogen ambient at 450C for 1min, the ideality factor decreases from 2.18 to 1.58, and series resistance decreases from 363 to 207, and the barrier height increases from 0.77 to 1.04 eV with increasing temperature in a temperature range of 198-298 K. The ideality factor and series resistance of the Schottky contacts with annealing are higher than those without annealing, while the barrier height is lower than that without annealing at various temperatures.