After substantial investment in research and development over the last decade, silicon carbide materials and devices are coming of age. The concerted efforts that made this possible have resulted in breakthroughs in our understanding of materials issues such as compensation mechanisms in high-purity crystals, dislocation properties, and the formation of SiC/SiO2 interfaces, as well as device design and processing. The progress accomplished over the last eight years in SiC-based electronic materials is summarized in this issue of MRS Bulletin.

We discuss continuing materials technology improvements that have transformed silicon carbide from an intriguing laboratory material into a premier manufacturable semiconductor technology. This advancement is demonstrated by reduced micropipe densities as low as 0.22 cm−2 on 3-in.-diameter conductive wafers and 16 cm−2 on 100-mm-diameter conductive wafers. For high-purity semi-insulating materials, we confirm that the carbon vacancy is the dominant deep-level trapping state, and we report very consistent cross-wafer activation energies derived from temperature-dependent resistivity.Warm-wall and hot-wall SiC epitaxy platforms are discussed in terms of capability and applications. Specific procedures that essentially eliminate forward-voltage drift in bipolar SiC devices are presented in detail.

Silicon carbide is a promising semiconductor for advanced power devices that can outperform Si devices in extreme environments (high power, high temperature, and high frequency). In this article, we discuss recent progress in the development of passivation techniques for the SiO2/4H-SiC interface critical to the development of SiC metal oxide semiconductor field-effect transistor (MOSFET) technology. Significant reductions in the interface trap density have been achieved, with corresponding increases in the effective carrier (electron) mobility for inversion-mode 4H-SiC MOSFETs. Advances in interface passivation have revived interest in SiC MOSFETs for a potentially lucrative commercial market for devices that operate at 5 kV and below.

Silicon carbide power field-effect transistors, including power vertical-junction FETs (VJFETs) and metal oxide semiconductor FETs (MOSFETs), are unipolar power switches that have been investigated for high-temperature and high-power-density applications. Recent progress and results will be reviewed for different device designs such as normally-OFF and normally-ON VJFETs, double-implanted MOSFETs, and U-shaped-channel MOSFETs. The advantages and disadvantages of SiC VJFETs and MOSFETs will be discussed. Remaining challenges will be identified.

The successful commercialization of unipolar Schottky rectifiers in the 4H polytype of silicon carbide has resulted in a market demand for SiC high-power switching devices. This article reviews recent progress in the development of high-voltage 4H-SiC bipolar power electronics devices.We also present the outstanding material and processing challenges, reliability concerns, and future trends in device commercialization.

The recent discovery of forward-voltage degradation in SiC pin diodes has created an obstacle to the successful commercialization of SiC bipolar power devices. Accordingly, it has attracted intense interest around the world. This article summarizes the progress in both the fundamental understanding of the problem and its elimination.The degradation is due to the formation of Shockley-type stacking faults in the drift layer, which occurs through glide of bounding partial dislocations. The faults gradually cover the diode area, impeding current flow. Since the minimization of stress in the device structure could not prevent this phenomenon, its driving force appears to be intrinsic to the material. Stable devices can be fabricated by eliminating the nucleation sites, namely, dissociated basal-plane dislocations in the drift layer.Their density can be reduced by the conversion of basal-plane dislocations propagating from the substrate into threading dislocations during homoepitaxy.

Significant progress has been made in the development of SiC metal semiconductor field-effect transistors (MESFETs) and monolithic microwave integrated-circuit (MMIC) power amplifiers for high-frequency power applications. Three-inch-diameter high-purity semi-insulating 4H-SiC substrates have been used in this development, enabling high-volume fabrication with improved performance by minimizing surface- and substrate-related trapping issues previously observed in MESFETs. These devices exhibit excellent reliability characteristics, with mean time to failure in excess of 500 h at a junction temperature of 410°C. A sampling of these devices has also been running for over 5000 h in an rf high-temperature operating-life test, with negligible changes in performance. High-power SiC MMIC amplifiers have also been demonstrated with excellent yield and repeatability. These MMIC amplifiers show power performance characteristics not previously available with conventional GaAs technology. These developments have led to the commercial availability of SiC rf power MESFETs and to the release of a foundry process for MMIC fabrication.