DMOS transistors having trenched gate oxide
First Claim
1. A DMOS device includes a core cell area comprising a plurality of trenched DMOS cells and a gate metal area for forming a gate metal therein near a termination area disposed on an outer peripheral of said DMOS device, wherein said DMOS device include a plurality of trenched poly-fingers extending from trenched poly-gates of said DMOS cells to said gate metal area provided with a trench-end region defining a plurality of trench corners therein, said DMOS device further comprising:
- an above-trench poly-runner layer covering said gate metal area including said trench-end region and said above-trench poly-runner layer is connected to said poly-fingers wherein said above-trench poly runner layer defining a plurality of gate contact openings provided for depositing a metal therein to contact said trenched poly-fingers and said trenched gates; and
a gate contact opening is disposed above each of said trench corners whereby none of said trench corners being covered by said above-trench poly-runner layer.
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Accused Products
Abstract
Improved power MOSFET structure, and fabrication process are disclosed in this invention to achieve cost savings by simplified device structure and fabrication processes, and also by reducing the required die size. Specifically, in a novel MOSFET device, insulation of mobile ions are achieved by extending the poly gate and metal contacts such that the passivation layer is no longer required and the fabrication process is simplified such that the MOSFET device can be manufactured at a lower price. Furthermore, in another MOSFET device, the gate runner is used to replace the field plate such that the requirement of a field plate as that in a conventional MOSFET device is also eliminated and, by reducing the die size, the cost of manufacture is further reduced.
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Citations
7 Claims
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1. A DMOS device includes a core cell area comprising a plurality of trenched DMOS cells and a gate metal area for forming a gate metal therein near a termination area disposed on an outer peripheral of said DMOS device, wherein said DMOS device include a plurality of trenched poly-fingers extending from trenched poly-gates of said DMOS cells to said gate metal area provided with a trench-end region defining a plurality of trench corners therein, said DMOS device further comprising:
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an above-trench poly-runner layer covering said gate metal area including said trench-end region and said above-trench poly-runner layer is connected to said poly-fingers wherein said above-trench poly runner layer defining a plurality of gate contact openings provided for depositing a metal therein to contact said trenched poly-fingers and said trenched gates; and a gate contact opening is disposed above each of said trench corners whereby none of said trench corners being covered by said above-trench poly-runner layer. - View Dependent Claims (2, 3)
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4. A trenched DMOS device with no above trench poly layer includes a core cell area comprising a plurality of trenched DMOS cells and a gate metal area for forming a gate metal therein near a termination area disposed on an outer peripheral of said DMOS device, wherein said trenched DMOS device includes a plurality of trenched poly-fingers extending from trenched poly-gates of said DMOS cells to said gate metal area thus forming a trench-end region, said DMOS device further comprising:
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a trenched gate-runner having a width substantially larger than said poly-fingers in said trench-end region comprising trenched polysilicon and connected to an end point of said poly-fingers wherein said trenched polysilicon in said trenched gates, said poly-fingers and said gate runner are disposed in said trenches whereby said DMOS device includes no above trench polysilicon layer in contact with said trenched polysilicon; and an insulation layer covering an entire area around said trench-end region wherein said insulation layer defining a plurality of openings provided for metal contacts including a plurality of gate contact openings above said gate runner provided for filling a gate metal therein for contacting said poly-fingers and said gate therefrom. - View Dependent Claims (5, 6, 7)
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Specification