The Effect of Reduced Oxidation Process Using Ammonia Annealing and Deposited Oxides on 4H-SiC Metal-Oxide-Semiconductor Structure

Abstract

Nitric oxide (NO) post-oxidation annealing (POA) is an effective method for lowering the carbon component at an oxide/4H-SiC interface. However, this method has a drawback of additional oxidation by oxygen source from the NO gas. Atomic-layer-deposited (ALD) oxides subjected to ammonia (NH 3) annealing were employed to realize nitridation without oxidation process. Because NH 3annealed oxides have a drawback of high leakage current, deposition of dielectrics on ALD SiO 2 with subsequent NH 3 annealing were performed to reduce leakage current and to prevent oxidation, respectively. The employments of this process reduced interface trap density and surface roughness effectively while maintaining low leakage current.

Effect of sweeping direction on the capacitance−voltage behavior of sputtered SiO2/4H-SiC metal-oxide semiconductors after nitric oxide post-deposition annealing

“…4H-silicon carbide (SiC) is a wide-bandgap material with high breakdown voltage, high thermal conductivity, and fast saturation drift velocity [1][2][3][4]. The 4H-SiC metal-oxide semiconductor (MOS) has replaced traditional silicon devices for high-voltage, high-temperature, and fast-switching applications [4][5][6][7][8][9]. Thermal oxidation can form SiO 2 as gate oxide on 4H-SiC.…”

“…Postannealing using nitric oxide or nitric dioxide decreases the interface trap density of 4H-SiC MOS [13][14][15][16]. Deposition technologies, such as chemical vapor deposition [17,18] and atomic layer deposition [8,9,19], also form the gate oxide on 4H-SiC MOS even in the absence of high temperatures.…”