摘要 |
A semiconductor on insulator device has an insulator layer, an active layer (40) on the insulator layer, a lateral arrangement of collector (10), emitter (30) and base (20) on the active layer, and a high Base-dose region (70) extending under the emitter towards the insulator to suppress vertical current flowing under the emitter. This region (70) reduces the dependence of current-gain and other properties on the substrate (Handle-wafer) voltage. This region can be formed of the same doping type as the base, but having a stronger doping. It can be formed by masked alignment in the same step as an n type layer used as the body for a P-type DMOS transistor. |