We report the results of measurements conducted on the electrical breakdown of high resistivity (- 20 K/spl Omega/-cm) single crystal silicon. The salient features of the measurements are briefly described below. The voltage-current data shows space charge limited conduction for applied voltage below pre-breakdown. The measurement of the decrease in the time delay between the applied voltage and the breakdown current exhibited a linear dependence on the applied voltage. The pulse forming network used in our measurements had an internal impedance (- 260 /spl Omega/) which limited the peak power applied to the sample and it permitted repeated breakdown shots without "damaging" the silicon surface. This feature allowed us to study of the effect of voltage conditioning of the sample with applied voltage exceeding breakdown threshold of the unsullied sample. A higher holdoff voltage was obtained after conditioning the sample with 100 shots where the applied voltage was at or near the breakdown condition. Conditioning was reversed through exposure to laboratory air but not to dry nitrogen. Water vapor and/or oxygen seem to play a significant role in the sample's conditioning and its reversal. The major species desorbed during breakdown were identified using a mass spectroscopic technique. It seems that the desorbed species are released by hermally initiated surface (not bulk) processes due to localized high current density filaments on or near the surface. During a typical surface breakdown shot approximately 10/sup 12/ electrons are injected into the sample whereas, the pressure rise obtained under high vacuum condition (base pressure=3x10/sup -8/ torr) indicates that approximately 10/sup 14/ atoms or molecules are desorbed. The resulting pressure change due to the surface breakdown is approximately linearly proportional to the peak power while the deposited energy vs. pressure change does not follow the same behavior. Also, the thermal description mass spectrogram agrees with the desorption mass spectrogram obtained form our silicon surface flashover. these results suggest that for silicon the gas description udring breakdown in a thermal process and is not due to electron impact description or other cascade processes. Our work supports the thermal description hypothesis of other researchers.
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