Properties of AlGaN/GaN Ni/Au-Schottky diodes on 2°-off silicon carbide substrates

Abstract

The current-voltage characteristics of planar Ni/Au Schottky diodes fabricated on top of AlGaN/GaN structures with two different surface miscut, 0.5 and 28-off, were measured at elevated temperatures of up to 580 K and then discussed. The Schottky contact parameters, such as ideality factor (n) and barrier height (w b ), were extracted by a commonly used thermionic emission approach, combined with Norde's method. In this study, we show that the temperature shift of the Schottky barrier height for a structure with 0.58-off is equal to À0.5V/100 K, which is close to the value obtained for the temperature dependence of the energy band gap for GaN. We found that for both types of structures the ideality factor decreases with the temperature increase, while the barrier height increases. Finally, we observed some differences in the leakage current mechanism and thermionic behavior, which we attribute to differences in surface homogeneity of diodes fabricated on different surface miscut.

AlGaN/GaN on SiC Devices without a GaN Buffer Layer: Electrical and Noise Characteristics

“…The barrier height found based on the thermionic emission (TE) model was φ = 0.75 eV. These values are typical for Ni/AlGaN Schottky barriers [ 31 ]. Under reverse bias, leakage currents were saturated at approximately −5 V and remained constant until the breakdown (see Figure 6 b).…”

Vertical GaN Schottky Diodes Grown on Highly Conductive Ammono-GaN Substrate

“…It is well known that electron transport from metal to semiconductor can be described by simple thermionic emission theory (TE). Thereby, the Schottky barrier height and ideality factor (n) can be easily estimated [11]. In this theory the forward current as a function of voltage is given by…”

“…The diodes surface was not passivated. More details on the sample preparation can be find elsewhere [11].…”

Development of AlGaN/GaN/SiC high-electron-mobility transistors for THz detection

“…Although the first high-electron-mobility transistors (HEMTs) and Schottky diodes (SDs) have been demonstrated on the AlGaN/GaN grown on a native GaN substrate [5], its further development is limited by the high price and small volume production of the GaN crystals. Thus, to make progress in the GaN technology, AlGaN/GaN structures grown on foreign substrates such as silicon [6], sapphire [7], and SiC [8] have been explored. Usually the AlGaN/GaN structures with less demanding performance are fabricated on sapphire or silicon substrates.…”