4H-SiC Wafers Studied by X-Ray Absorption and Raman Scattering

Abstract

Synchrotron radiation X-ray absorption and UV 325 nm excitation Raman scattering- photoluminescence (PL) have been employed to investigate a series of 4H-SiC wafers, including bulk, epitaxial single or multiple layer structures by chemical vapor deposition. Significant results on the atomic bonding and PL-Raman properties are obtained from these comparative studies.

X-ray Absorption Fine Structural Study of Atomic Structures and Chemical States of Dopants in 4H-SiC(0001)

“…Silicon carbide (SiC), a wide bandgap semiconductor with an indirect band structure, is attractive as a semiconductor for its excellent physical and electronic properties. − SiC exhibits a large band gap (2.3 to 3.2 eV), high temperature coefficient, high critical field strength (4–6 MV cm –1 ), and high chemical stability. − SiC-based devices show high breakdown voltage, high switching speed, and high-temperature operation. ,, …”

“…Among the polytypes, 4H-SiC(0001) has received the most attention due to its second-highest bandgap (3.2 eV) and isotropic mobility along the crystal a - and c -axes . 4H-SiC(0001) is commercially available in a wafer form. − Nitrogen (N) and phosphorus (P) are used as n-type dopants, whereas aluminum (Al) and boron (B) are used in the case of p-type 4H-SiC. , …”

GaN Films under Different Growth Mechanisms Studied by Synchrotron X-ray Absorption Spectroscopy

“…We have in recent years employedSR X-ray absorption spectroscopy (XAS) to investigate different materials, such as SiC, CdZnTe, MgZnO, AlGaN, etc. [9][10][11][12]. In this paper, we perform a SRextended X-ray absorption fine structure (EXAFS) investigation for GaN thin films grown on sapphire and on Si.…”