Koninklijke Philips Corporation N.v.

Mark A Gajda

Erwin Hijzen

Michael A A In 't Zandt

The trench-gate () of, for example, a cellular power MOSFET comprises doped poly-Si or other semiconductor material () adjacent to the gate dielectric layer () adjacent to the channel-accommodating region () of the device. The gate () also comprises a sizeable silicide part () that reduces gate resistance. This silicide part () protrudes upwardly from the trench () over a distance (z) typically larger than the width (w) of the trench (), so forming an upstanding part () of a metal silicide material between its top and sidewalls above the level of the body surface (). The gate dielectric layer () at least adjacent to the channel-accommodating region () is protected from the metal silicide by at least the semiconductor part () of the gate and by the protrusion (z) of the silicide part () upwardly above the level of the body surface (). The height (z) of this silicide protrusion can be defined by a layer thickness of a mask () with a window () at which the trench () is etched. The silicide material may be deposited or grown in situ by alloying.

Trench-gate semiconductor devices, and their manufacture

In a cellular power MOSFET or other semiconductor device, a wide connection across the perimeter of an active device area ( ) is replaced with a plurality of narrower conducting fingers ( ). The fingers ( ) are used as follows in providing a doped edge region ( ) that is required below the connection ( ). Dopant ( ) is implanted at spaces ( ) between and beside the fingers ( ) and is diffused to form a single continuous region ( ) extending beneath the fingers ( ) and at the spaces ( ) therebetween. This doped edge region ( ) may be, for example, a deep guard ring in an edge termination of a power MOSFET, or an extension of its channel-accommodating region ( ). A trench-gate network ( ) of the MOSFET can be connected by the conducting fingers to a gate bond pad and/or field plate ( ).

Semiconductor devices and their manufacture

The trench-gate ( ) of, for example, a cellular power MOSFET comprises doped poly-Si or other semiconductor material ( ) adjacent to the gate dielectric layer ( ) adjacent to the channel-accommodating region ( ) of the device. The gate ( ) also comprises a sizeable silicide part ( ) that reduces gate resistance. This silicide part ( ) protrudes upwardly from the trench ( ) over a distance (z) typically larger than the width (w) of the trench ( ), so forming an upstanding part ( ) of a metal silicide material between its top and sidewalls above the level of the body surface ( ). The gate dielectric layer ( ) at least adjacent to the channel-accommodating region ( ) is protected from the metal silicide by at least the semiconductor part ( ) of the gate and by the protrusion (z) of the silicide part ( ) upwardly above the level of the body surface ( ). The height (z) of this silicide protrusion can be defined by a layer thickness of a mask ( ) with a window ( ) at which the trench ( ) is etched. The silicide material may be deposited or grown in situ by alloying.

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Stockport, United Kingdom

Mark A Gajda