Lateral super-junction MOSFET device and termination structure

摘要

A lateral superjunction MOSFET device includes a gate structure, a first column connected to the lateral superjunction structure and a second column disposed in close proximity to the first column. The lateral superjunction MOSFET device includes the first column to receive current from the channel when the MOSFET is turned on and to distribute the channel current to the lateral superjunction structure functioning as the drain drift region. The second column disposed near the first column is used to pinch off the first column when the MOSFET device is to be turned off and to block the high voltage being sustained by the MOSFET device at the drain terminal from reaching the gate structure. In some embodiments, the lateral superjunction MOSFET device further includes termination structures for the drain, source and body contact doped region fingers.

主权项

1. A lateral superjunction MOSFET device, comprising:
a semiconductor base layer comprising a heavily doped semiconductor substrate of a first conductivity type and a lightly doped semiconductor layer of the first conductivity type formed on the substrate, the substrate forming a bottom source electrode of the MOSFET device; a semiconductor body formed on the semiconductor base layer and comprising a lateral superjunction structure including a plurality of alternating N-type and P-type thin semiconductor regions formed substantially in parallel with a major surface of the semiconductor body, the alternating N-type and P-type thin semiconductor regions forming a drain drift region of the MOSFET device; a body region of the first conductivity type formed in a first surface of the semiconductor body, the first surface being opposite the semiconductor base layer; a conductive gate formed on the semiconductor body at a near end of the lateral superjunction structure and insulated from the semiconductor body by a gate dielectric layer; a source region of a second conductivity type, opposite the first conductivity type, formed in the body region and formed self-aligned with a first end of the conductive gate, the source region extending under the first end of the conductive gate to form a small overlap; a body contact region of the first conductivity type formed in the body region and adjacent to the source region; a drain region of the second conductivity type formed at a distant end of the lateral superjunction structure, the drain region extending through the lateral superjunction structure; a first column of the second conductivity type formed under the conductive gate and spaced apart from the source region, the region of the semiconductor body under the conductive gate between the source region and the first column forming a channel of the MOSFET device, the first column extending through the lateral superjunction structure and is electrically unbiased; and a second column of the first conductivity type formed under and in electrical contact with the body contact region, the second column extending through the lateral superjunction structure, wherein the first column distributes a current from the channel of the MOSFET device in an on-state to the drain drift region formed by the lateral superjunction structure to be collected by the drain region, and the second column pinches off the first column in an off-state of the MOSFET device to isolate the conductive gate from a drain voltage at the drain region.