Karl Brack

X‐Ray Method for the Determination of the Polarity of SiC Crystals

The semiconductor SiC is a polar compound. As a consequence the opposite faces of {00.1} wafers have different chemical properties and hence different etch patterns. These differences, however, give no convincing evidence as to which side is the Si side and which is the C side of a SiC single crystal. Theoretically, small differences in x‐ray reflection intensities are shown to be expected from opposite crystal faces. By careful crystal surface preparation these differences could experimentally be verified. Thus the proper correlation between the Si or C face and the etch patterns has been established.

Resistivity and annealing properties of implanted Si:H+

Abstract N- or p-type 1 ohm-cm resistivity silicon crystals are bombarded with 1 MeV protons to doses greater than 1015 H+/cm2. The crystals are characterized through X-ray topography and surface and in-depth resistivity measurement techniques. Post-bombardment measurements indicate a high resistance layer (104 ohm-cm range on the silicon surface, extending to 16μm depth after 1 MeV H+ bombardment. Post-anneal results show that this insulating layer is still stable after 300 °C anneal cycles. At higher anneal temperatures the radiation damage starts to anneal out and at 800 °C the crystal returns to its original resistivity.