Trench-gate semiconductor devices, and their manufacture
First Claim
1. A trench-gate semiconductor device comprising a gate trench that extends into a semiconductor body from a body surface, through a channel-accommodating region between a source region and an underlying drain region, whereinthe gate, present in the trench, is capacitively coupled to the channel-accommodating region by an intermediate gate dielectric layer at a wall of the trench, the gate comprises a part of semiconductor material adjacent to the gate dielectric layer adjacent to the channel-accommodating region, the gate protrudes upwardly from the trench in the form of a silicide upstanding part which is of a metal silicide material between its top and sidewalls above the level of the body surface, and the gate dielectric layer at least adjacent to the channel-accommodating region is separated from the metal silicide material by at least the semiconductor part of the gate and by the protrusion of the silicide part upward above the level of the body surface.
4 Assignments
0 Petitions
Accused Products
Abstract
The trench-gate (11) of, for example, a cellular power MOSFET comprises doped poly-Si or other semiconductor material (11a) adjacent to the gate dielectric layer (17) adjacent to the channel-accommodating region (15) of the device. The gate (11) also comprises a sizeable silicide part (11b) that reduces gate resistance. This silicide part (11b) protrudes upwardly from the trench (20) over a distance (z) typically larger than the width (w) of the trench (20), so forming an upstanding part (11b) of a metal silicide material between its top and sidewalls above the level of the body surface (10a). The gate dielectric layer (17) at least adjacent to the channel-accommodating region (15) is protected from the metal silicide by at least the semiconductor part (11a) of the gate and by the protrusion (z) of the silicide part (11b) upwardly above the level of the body surface (10a). The height (z) of this silicide protrusion can be defined by a layer thickness of a mask (51,52; 510,520) with a window (51a, 510a) at which the trench (20) is etched. The silicide material may be deposited or grown in situ by alloying.
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Citations
6 Claims
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1. A trench-gate semiconductor device comprising a gate trench that extends into a semiconductor body from a body surface, through a channel-accommodating region between a source region and an underlying drain region, wherein
the gate, present in the trench, is capacitively coupled to the channel-accommodating region by an intermediate gate dielectric layer at a wall of the trench, the gate comprises a part of semiconductor material adjacent to the gate dielectric layer adjacent to the channel-accommodating region, the gate protrudes upwardly from the trench in the form of a silicide upstanding part which is of a metal silicide material between its top and sidewalls above the level of the body surface, and the gate dielectric layer at least adjacent to the channel-accommodating region is separated from the metal silicide material by at least the semiconductor part of the gate and by the protrusion of the silicide part upward above the level of the body surface.
Specification