Koninklijke Philips Corporation N.V.

Peter J Forbes

Steven Thomas Peake

Raymond J Grover

Christopher Martin Rogers

Georgios Petkos

Robert J Farr

Compact trench-gate semiconductor devices, for example a cellular power MOSFET with sub-micron pitch (Yc), are manufactured with self-aligned techniques that use sidewall spacers ( ) in different ways. Thereby, the source region ( ) and a contact window ( ) for a source electrode ( ) can be self-aligned to a narrow trench ( ) containing the trench-gate ( ). Thereby, the channel-accommodating region ( ) can also be provided after forming the trench-gate ( ), and with very good control of its doping concentration (Na; p) adjacent to the trench ( ). To achieve this control, its dopant is provided after removing the spacers ( ) from the mask ( ) so as to form a doping window ( ), which may also be used for the source dopant, adjacent to the trench-gate ( ). A high energy dopant implant ( ) or other doping process provides this channel dopant adjacent to the trench ( ) and extending laterally below the mask ( ). A remarkably uniform doping profile can be achieved beneath the doping window ( ) and beneath the mask ( ). By using a high ion energy and high dose, the dopant ions ( ) at the doping window ( ) can be laterally scattered below the mask ( ) while those at the mask ( ) penetrate there-through to be implanted in the underlying portion of the body ( ).

Trench-gate semiconductor devices having a channel-accommodating region and their methods of manufacture

Compact trench-gate semiconductor devices, for example a cellular power MOSFET with sub-micron pitch (Yc), are manufactured with self-aligned techniques that use sidewall spacers ( ) in different ways. The trench-gate ( ) is accommodated in a narrow trench ( ) that is etched via a narrow window ( ) defined by the spacers ( ) at sidewalls of a wider window ( ) of a mask ( ) at the body surface ( ). The spacers ( ) permit a source region ( ) adjacent to the trench-gate ( ) and an insulating overlayer ( ) over the trench-gate ( ) to be self-aligned to this narrow trench ( ). The overlayer ( ), which defines a contact window ( ) for a source electrode ( ), is provided in a simple but reproducible manner by deposition and etch-back, after removing the spacers ( ). Its overlap (y , y &prime;) with the body surface ( ) is well-defined, so reducing a short-circuit risk between the source electrode ( ) and the trench-gate ( ). Furthermore, implantation of the source region ( ) is facilitated, and a channel-accommodating region ( ) can also be provided using a high energy implant ( ) after providing the insulating overlayer ( ).

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Peter J Forbes