SOME CRITICAL CONDITIONS OF THE THERMAL BREAKDOWN IN SEMICONDUCTORS

The recent spread of wide bandgap semiconductors in device practice ma kes necessary the more fundamental general study of critical condition s of the static thermal breakdown in semiconductors. dU/dI = 0 conditi ons on the I-V characteristics indicating the breakdown phenomena have been calculated in this work for the different conductivity ranges ba sed on the analytical description of the thermal generation of charge carriers and that of the mobility variation on the temperature. The te mperature increase compared to the ambient temperature, necessary for the turnover of the thermal balance of the system, has been calculated from these primary statistical principles of the semiconductors. It i s shown that the breakdown conditions and the difference between the b reakdown temperature and that of the ambient depend either merely on t he activation energy of impurities independently of the semiconductor or on the bandgap width of the given semiconductor. Temperature region s are indicated where no thermal breakdown can occur. (C) 1998 Elsevie r Science S.A. All rights reserved.