Electrical Conductivity Improvement of Point Defects in 4H-SiC

Abstract

Owing to its high melting temperature, the 4H-SiC substrate exhibits numerous defects that are difficult to remove, hindering the development of large-scale, high electrical conductivity 4H-SiC substrates. This study constructs and analyzes atomic models of point defects in 4H-SiC, focusing mainly on Si and C atom vacancies and interstitial defects. Point defects in 4H-SiC can increase the electrical conductivity. For example, the Si0 vacancy has been found to enhance the electrical conductivity of a 4H-SiC unit cell by more than 220 times, converting its wide bandgap property to metallic. The research demonstrates that defects can improve 4H-SiC properties, paving the way for defect-selective technology to develop large-scale, high electrical conductivity 4H-SiC substrates.

Advances and challenges in 4H silicon carbide: defects and impurities

“…Vacancy defects can be introduced during growth process or material handling, such as controlling carrier lifetime through electron irradiation or fabricating isolation layers via ion implantation [36][37][38][39][40][41]. These vacancy defects often created deep energy levels within the band gap of crystals, thereby exerting a profound impact on the electrical and optical properties of the materials [42,43].…”

“…In recent years, researchers found the hierarchy of Si inter mainly depended on the site of the Fermi energy level, which was a direct consequence of the presence of deep interstitial layers, but the C inter was found for a different hierarchy [74,75]. Besides, scientists also found the mobile intrinsic defects-interstitials plays a key role in the self-diffusion and doping-diffusion of ion-implanted processing as well as annealing processing [40,76]. However, there are not many reports about the interstitials in 4H-SiC recently.…”

Exploring Defect Dynamics and Twin-Layer Interactions in SiC Crystals through Molecular Simulations

“…However, research on SiC crystal growth, while extensive, − often overlooks the impacts and interrelations of different crystal structures. Defects in these structures, such as point, line, and surface defects, can significantly deteriorate device performance, leading to increased leakage currents and damage. − These defects can also degrade the optical performance of devices, affecting the efficiency of LEDs and the sensitivity of photodetectors. , Effective identification and management of these defects are crucial for optimizing device performance.…”