| 摘要 |
<p>A trench-gate MOSFET or ACCUFET has its gate (21) in a first trench (20) that extends through a channel-accommodating body region (15) to a drain region (14). Within the transistor cells, a second trench (40) comprising deposited highly-doped semiconductor material (41) such as highly-doped polysilicon extends to the drain region (14). This highly-doped material (41) is of opposite conductivity type to the drain region (14) and, together with a possible out-diffusion profile (42), forms a localised region (41, 42) that is separated from the first trench (20) by the body region (15). A source electrode (23) contacts the source region (13) and the whole top area of the localised region (41, 42). In a MOSFET, the localised region (41, 42) provides protection against turning on of the cell's parasitic bipolar transistor. In an ACCUFET, the localised region (41, 42) depletes the channel-accommodating body region (15A).</p> |
