High frequency switching MOSFETs with low output capacitance using a depletable P-shield
First Claim
1. A MOSFET device, comprising:
- a semiconductor substrate of a first conductivity type wherein the substrate includes a lightly doped epitaxial region in a top portion of the substrate;
a body region of a second conductivity type formed in a top portion of the semiconductor substrate, wherein the second conductivity type is opposite the first conductivity type;
a plurality of active device structures formed from the semiconductor substrate and body region, wherein each active device structure in the plurality of active device structures comprises a gate electrode in a gate trench formed in the semiconductor substrate, wherein the gate electrode is insulated from the substrate and body region by a gate oxide, whereby there are a plurality of gate electrodes in a corresponding plurality of gate trenches;
a depletable shield of the second conductivity type formed in the semiconductor substrate between first and second gate trenches of the plurality of gate trenches and extending vertically from above a gate trench bottom down to below the gate trench bottom and separated from the body region by a drift region of the first conductivity type, wherein the depletable shield is electrically connected to the body region;
an insulative layer over a top surface of the body region;
a conductive source metal layer formed over the insulative layer; and
one or more electrical connections that connect the source metal layer with one or more source regions.
1 Assignment
0 Petitions
Accused Products
Abstract
Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers. The MOSFETS also may include a depletable shield in a lower portion of the substrate. The depletable shield may be configured such that during a high drain bias the shield substantially depletes. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
-
Citations
12 Claims
-
1. A MOSFET device, comprising:
-
a semiconductor substrate of a first conductivity type wherein the substrate includes a lightly doped epitaxial region in a top portion of the substrate; a body region of a second conductivity type formed in a top portion of the semiconductor substrate, wherein the second conductivity type is opposite the first conductivity type; a plurality of active device structures formed from the semiconductor substrate and body region, wherein each active device structure in the plurality of active device structures comprises a gate electrode in a gate trench formed in the semiconductor substrate, wherein the gate electrode is insulated from the substrate and body region by a gate oxide, whereby there are a plurality of gate electrodes in a corresponding plurality of gate trenches;
a depletable shield of the second conductivity type formed in the semiconductor substrate between first and second gate trenches of the plurality of gate trenches and extending vertically from above a gate trench bottom down to below the gate trench bottom and separated from the body region by a drift region of the first conductivity type, wherein the depletable shield is electrically connected to the body region;
an insulative layer over a top surface of the body region;
a conductive source metal layer formed over the insulative layer; and
one or more electrical connections that connect the source metal layer with one or more source regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
Specification