Deep Trench MOS Barrier Junction All Around Rectifier and MOSFET
First Claim
1. A rectifier device, 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 third p-type semiconductor layer deposed on top of the second n-type semiconductor layer;
a first enclosed deep trench etched in ring shape along periphery of the rectifier device and from top of the third p-type semiconductor layer down to bottom the second n-type semiconductor layer; and
a second enclosed deep trench running parallel to the first enclosed deep trench but with smaller radius, etched from the top of the third p-type semiconductor layer down to the bottom the second n-type semiconductor layer;
wherein both the first and second enclosed deep trenches have substantially the same depth.
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Accused Products
Abstract
Apparatus and other embodiments associated with high speed and high breakdown voltage 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 ring shape enclosed a vertical P-N junction. For each deep trench, a corresponding wider ring-shape P+ region is created on top of a N− epi layer. This enclosed deep trench surrounding a vertical P-N junction and a thinner N− epitaxial layer allow higher reverse bias voltage and low leakage current. In another embodiment, an enclosed deep trench in ring shape surrounds a horizontal P-N junction, which results in a planar N-channel MOS during forward bias. The structure can be extended to multiple deep trenches with associated horizontal P-N junctions. In a further embodiment, an enclosed deep trench in ring shape surrounds a vertical MOS structure plus a shallow trench gate in the center to create yet another device with very high breakdown voltage and very low leakage current. This structure can be extended to multiple deep trenches and shallow trenches as well.
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Citations
18 Claims
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1. A rectifier device, comprising:
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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 third p-type semiconductor layer deposed on top of the second n-type semiconductor layer; a first enclosed deep trench etched in ring shape along periphery of the rectifier device and from top of the third p-type semiconductor layer down to bottom the second n-type semiconductor layer; and a second enclosed deep trench running parallel to the first enclosed deep trench but with smaller radius, etched from the top of the third p-type semiconductor layer down to the bottom the second n-type semiconductor layer; wherein both the first and second enclosed deep trenches have substantially the same depth. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A MOSFET, comprising:
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a first semiconductor layer of a first type of dopant; a second semiconductor layer of the first type of dopant deposed above the first semiconductor layer, and with lower doping concentration but larger depth than that of the first semiconductor layer; a third semiconductor layer of a second type of dopant deposed above the second semiconductor layer, wherein the first type of dopant and the second type of dopant have opposite polarity; a fourth semiconductor layer of the first type of dopant deposed above the third semiconductor layer, and with higher doping concentration than that of the second semiconductor layer; and a first enclosed deep trench etched from top of the fourth semiconductor layer down to bottom of the second semiconductor layer, and along the periphery of the MOSFET, with oxide layer on its sidewalls and bottom surface, and a polysilicon layer above the oxide layer. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A MOSFET, comprising:
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a first semiconductor layer of a first type of dopant; a second semiconductor layer of the first type of dopant deposed above the first semiconductor layer, and with lower doping concentration but larger depth than that of the first semiconductor layer; a third semiconductor layer of a second type of dopant deposed above the second semiconductor layer, wherein the first type of dopant and the second type of dopant have opposite polarity; and a first enclosed deep trench etched from top of the third semiconductor layer down to bottom of the second semiconductor layer, and along the periphery of the MOSFET; and two fourth semiconductor regions of the first type of dopant deposed in the upper part of the third semiconductor layer and on both sides of the first enclosed deep trench, wherein the first enclosed deep trench has oxide layer on its sidewalls and bottom surface, and a polysilicon layer above the oxide layer. - View Dependent Claims (16, 17, 18)
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Specification