Self-heating enhanced impact ionization in SOI MOSFETs

Impact ionization (II) originates from energetic carriers in the channel. The II current is not only a monitor of device reliability, but also affects the current drive of partially-depleted (PD) SOI transistors by charging up the floating body and hence varying the threshold voltage. Due to the low thermal conductivity of buried oxide, SOI MOSFETs are susceptible to the local thermal heating generated in the channel. This SOI-specific self-heating effect (SHE) provides a source for carrier heating, which may determine impact ionization. In this paper we report an enhanced impact-ionization phenomenon caused by SHE in SOI MOSFETs.