This paper reviews research on advanced bulk crystal growth of SiC. A brief review highlights the benefits of the so called Modified Physical Vapor Transport Technique which uses an additional gas pipe for fine tuning of the growth cell of a conventional Physical Vapor Transport setup with additional gases. Main emphasis, however, will be laid on a systematic dislocation evolution study for various growth parameter sets. Besides doping, growth temperature was considered. Two main results were found: (i) In p‐type SiC, irrespective of the incorporation of aluminum or boron acceptors, basal plane dislocations that are harmful for bipolar power devices appear less pronounced or are even absent compared to n‐type SiC. (ii) Growth at elevated seed temperature (i.e. 2300 °C and higher) is beneficial for low dislocation densities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Silicon carbide as a material for electronic devices still has substantial problems concerning its structural quality and defects. It has been shown that dopants can have a big influence on structural properties like polytype stability and dislocation statistics [1]. We will discuss the effect of an isoelectronic dopant in silicon carbide. Germanium, being a member of the 4th group in the periodic table of elements like silicon and carbon, will not influence the electrical properties of the material such as e.g. aluminum. In our experiments we reached concentrations of up to 1*1020 cm-3. We have observed an impact on the polytype stability during sublimation growth with in-situ germanium incorporation. We investigated an influence on the dislocation statistics during growth and, hence, varying germanium concentration. We found only a slight decrease in mobility during Hall measurements but no severe changes in electrical properties of the material.

We have investigated thermally induced strain in the SiC crystal lattice during physical vapor transport bulk growth. Using high energy x-ray diffraction lattice plane bending was observed in-situ during growth. With increasing growth rate increasing lattice plane bending and, hence, strain was observed. A comparison with numerical modeling of the growth process shows that the latter is related to the heat of crystallization which needs to be dissipated from the crystal growth front. The related temperature gradient as driving force for the dissipation of the heat of crystallization causes lattice plane bending. Optimization of the growth process needs to consider such effects.

This work reports on the in-situ observation of a polytype switch during physical vapor transport (PVT) growth of bulk SiC crystals by x-ray diffraction. A standard PVT reactor for 2” and 3” bulk growth was set up in a high-energy x-ray diffraction lab. Due to the high penetration depth of the high-energy x-ray beam no modification of the PVT reactor was necessary in order to measure Laue diffraction patterns of the growing crystal with good signal to noise ratio. We report for the first time upon the in-situ observation of polytype switching during SiC bulk PVT growth.