Deep trench surrounded MOSFET with planar MOS gate
AssigneeChampion Microelectronic Corp.
InventorsHaiping Dun, Hung-Chen Lin
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Abstract
Apparatus and other embodiments associated with high speed and high breakdown voltage MOS rectifier are disclosed. A Junction All Around structure, where a deep trench structure surrounds and encloses a P-N junction or a MOS structure, is created and applied in various rectifiers. In one embodiment, multiple deep trenches in concentric ring circles enclosed several horizontal P-N junctions in concentric ring circles. In another embodiment, an enclosed deep trench in ring circle surrounds a horizontal P-N junction, which results in a planar N-channel MOS during forward bias. This structure can be extended to multiple deep trenches with associated horizontal P-N junctions.
Claims10
A MOSFET, comprising:
- a first n-type semiconductor layer;
- a second n-type epitaxial semiconductor layer with lower doping concentration but larger depth than that of the first n-type semiconductor layer, deposed on top of the first n-type semiconductor layer;
- a p-type semiconductor layer deposed on the top surface of the second n-type semiconductor layer;
- a metal layer deposed above the p-type semiconductor layer;
- at least two enclosed operating deep trenches in concentric continuous ring circles
- comprising a first deep trench and a second deep trench, wherein
- the first operating deep trench etched from the top of the p-type semiconductor layer down to the interface of the first n-type semiconductor layer and the second n-type semiconductor layer;
- the second operating deep trench etched from the top of the p-type semiconductor layer down to the interface of the first n-type semiconductor layer and the second n-type semiconductor layer, and the first operating deep trench has smaller radius than the second operating deep trench;
- a first set of two third n-type semiconductor in continuous ring circles deposed in the upper part of the p-type semiconductor layer and being adjacent to both inner-side and outer-side of the first enclosed deep trench but not in direct contact with the first enclosed deep trench;
- and
- a second set of two third n-type semiconductor in continuous ring circles deposed in the upper part of the p-type semiconductor layer and being adjacent to both inner-side and outer-side of the second enclosed deep trench but not in direct contact with the second enclosed deep trench.
Dependencies are inferred from the claim text.