Ni/Ag Schottky contacts on Al_0.11Ga_0.89N grown on Si (1 1 1) substrate by plasma-assisted MBE

Abstract

Al 0.11 Ga 0.89 N/GaN samples are grown by plasma-assisted molecular beam epitaxy method on (1 1 1) silicon substrates. High purity gallium (7N) and aluminum (6N5) were used to grow Al 0.11 Ga 0.89 N, GaN, and AlN, respectively. The surface morphology, structural and optical properties of the sample has been investigated by scanning electron microscope (SEM), and high-resolution X-ray diffraction (HR-XRD), respectively. HR-XRD measurement showed that the sample has a typical diffraction pattern of hexagonal Al 0.11 Ga 0.89 N/GaN heterostructures. Ni/Ag bilayers are deposited on Al 0.11 Ga 0.89 N as the Schottky contacts. The effect of annealing in oxygen ambient on the electrical properties of Ni/Ag/Al 0.11 Ga 0.89 N is studied by currentvoltage measurement. The annealing at a temperature of 700°C for 10 min results in an increase in the ideality factor from 1.033 to 1.042 and an increase in the Schottky barrier height from 0.708 to 0.811 eV. Furthermore, the annealing in oxygen ambient also leads to an increase in the surface roughness of the contacts from 0.0098 to 0.1360 μm which is in agreement with the SEM results.

Electrical Characteristics of Thermally Stable Ag–Pd–Cu Alloy Schottky Contacts on n-Al0.6Ga0.4N

“…AlGaN-based semiconductors have attracted immense interest because of their advantages such as wide and variable bandgaps, fast response, low power consumption, and high breakdown voltage. For these reasons, AlGaN-based semiconductors have been widely used in diverse electronic and optoelectronic applications, for instance, ultraviolet-light emitting diodes (UV-LEDs), [1][2][3] high-electron-mobility transistors (HEMTs), [4][5][6] Schottky diodes, [7][8][9][10] solar-blind UV photodetectors, [11][12][13] and hydrogen detectors. 14,15 To further enhance the performance of these devices, the formation of high-quality Schottky and Ohmic contacts and analyses of the contact formation mechanisms are essential.…”

“…14,15 To further enhance the performance of these devices, the formation of high-quality Schottky and Ohmic contacts and analyses of the contact formation mechanisms are essential. In this regard, the electrical and physical properties of Schottky [7][8][9][10] and Ohmic [16][17][18] contacts on AlGaN have been widely characterized. For example, Sulmoni et al 18 examined the electrical and structural properties of V/Al/Ni/Au (15/90/20/ 30 nm) n-contacts on n-Al x Ga 1−x N (with Al mole fraction (x) varying from 0.75 to 0.95), which were annealed at 650 °C-950 °C.…”