Vertical transistor with high breakdown voltage and low on-resistance

摘要

A vertical metal/oxide/semiconductor (MOS) device such as a MOS-type field effect transistor (MOSFET) and insulated gate bipolar transistor (IGBT) is disclosed. The MOS device has surface regions (14) of one conductivity type which are extended portions of breakdown-voltage sustaining layer (12). The surface region (14) is surrounded by a well region (13) of the opposite conductivity type. The surface region (14) may be stripe-shaped, and the surface area ratio between surface region (14) and well region (13) including source regions (15) may be from 0.01 to 0.2. Another MOS device is disclosed, comprising a breakdown voltage sustaining layer (12) of one conductivity type, with well regions (14) of the opposite conductivity type located in layer (12) and guard rings (g1....g14, Fig. 13) surrounding the well region (14) and having the same conductivity type as the well regions (14). The devices have a high breakdown voltage and low on-resistance, facilitating reducing the tradeoff relationship between the on-resistance and the breakdown voltage so realising high speed switching.