The energy distribution of electron states at SiC/SiO2 interfaces produced by oxidation of various (3C, 4H, 6H) SiC polytypes is studied by electrical analysis techniques and internal photoemission spectroscopy. A similar distribution of interface traps over the SiC bandgap is observed for different polytypes indicating a common nature of interfacial defects. Carbon clusters at the SiC/SiO2 interface and near‐interfacial defects in the SiO2 are proposed to be responsible for the dominant portion of interface traps, while contributions caused by dopant‐related defects and dangling bonds at the SiC surface are not observed.

Electrical data obtained from deep level transient spectroscopy investigations on deep defect centers in the 3C, 4H, and 6H SiC polytypes are reviewed. Emphasis is put on intrinsic defect centers observed in as‐grown material and subsequent to ion implantation or electron irradiation as well as on defect centers caused by doping with or implantation of transition metals (vanadium, titanium, chromium, and scandium).

Experimental studies on aluminum (Al) and boron (B) implantation in 4H/6H SiC are reported; the implantation is conducted at room temperature or elevated temperatures (500 to 700 °C). Both Al and B act as “shallow” acceptors in SiC. The ionization energy of these acceptors, the hole mobility and the compensation in the implanted layers are obtained from Hall effect investigations. The degree of electrical activity of implanted Al/B atoms is determined as a function of the annealing temperature. Energetically deep centers introduced by the Al+/B+ implantation are investigated. The redistribution of implanted Al/B atoms subsequent to anneals and extended lattice defects are monitored. The generation of the B‐related D‐center is studied by coimplantation of Si/B and C/B, respectively.

The electronic structure of SiC/SiO2 interfaces was studied for different SiC polytypes (3C, 4H, 6H, 15R) using internal photoemission of electrons from the semiconductor into the oxide. The top of the SiC valence band is located 6 eV below the oxide conduction band edge in all the investigated polytypes, while the conduction band offset at the interface depends on the band gap of the particular SiC polytype. In the energy range up to 1.5 eV above the top of the SiC valence band, interface states were found. Their electron spectrum is similar to that of sp2-bonded carbon clusters in diamond-like a-C:H films suggesting the presence of elemental carbon at the SiC/SiO2 interfaces.

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An analysis of fast and slow traps at the interface of 4H–SiC with oxides grown in O2, N2O, and NO reveals that the dominant positive effect of nitridation is due to a significant reduction of the slow electron trap density. These traps are likely to be related to defects located in the near-interfacial oxide layer. In addition, the analysis confirms that the fast interface states related to clustered carbon are also reduced by nitridation.

While silicon carbide has been an industrial product for over a century, it is only now emerging as the semiconductor of choice for high-power, high-temperature, and high-radiation environments. From electrical switching and sensors for oil drilling technology to all-electric airplanes, SiC is finding a place which is difficult to fill with presently available Si or GaAs technology. In 1824 Jöns Jakob Berzelius published a paper which suggested there might be a chemical bond between the elements carbon and silicon. It is a quirk of history that he was born in 1779 in Linköping, Sweden where he received his early education, and now, 172 years later, Linkoping University is the center of a national program in Sweden to study the properties of SiC as a semiconductor.

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