Power MOS element and method for producing the same
First Claim
1. Power MOS element comprising:
- a drift region with a doping of a first doping type;
a channel region with a doping of a second doping type, said second doping type being complementary to said first doping type, and said channel region bordering on said drift region;
a source region with a doping of said first doping type, said source region bordering on said channel region;
a plurality of essentially parallel gate trenches spaced from one another defining an active region of said power MOS element and extending through said source region, said channel region and into said drift region, said gate trenches comprising an electrically conductive material which is electrically insulated from said source region, said channel region and said drift region by an insulator;
a connecting gate trench for connecting the gate trenches in an electrically conductive way, extending through said source region, said channel region and into said drift region, said connecting gate trench comprising an electrically conductive material which is electrically insulated from said source region, said channel region and said drift region by an insulator, said connecting gate trench being a circumferential trench comprising a first connecting region, a second connecting region, a first longitudinal region and a second longitudinal region, said first connecting region connecting first ends of said plurality of gate trenches to one another, said second connecting region connecting second ends of said plurality of gate trenches to one another, and said first and said second longitudinal regions connecting said first and said second connecting regions to each other in such a way that the active region which is defined by said plurality of gate trenches is completely surrounded by said connecting gate trench;
a source contact structure for contacting said source region;
a channel contact structure for contacting said channel region;
a gate contact for contacting said connecting gate trench, said gate contact being connected via a contact hole through said insulator of said connecting gate trench which is filled with an electrically conductive material to said electrically conductive material of said connecting gate trench.
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Abstract
A power MOS element includes a drift region with a doping of a first doping type, a channel region with a doping of a second doping type which is complementary to said first doping type and which borders on said channel region and said drift region, and a source region with a doping of said first doping type, said source region bordering on said channel region. Furthermore, said power MOS element includes a plurality of basically parallel gate trenches which extend to said drift region and which comprise an electrically conductive material which is insulated from the transistor region by an insulator. The individual gate trenches are connected by a connecting gate trench, a gate contact only being connected in an electrically conductive way to the active gate trenches via contact holes in said connecting gate trench. For producing, three photolithographic steps are sufficient, which serve to etch said gate trenches and said connecting gate trench, to produce said contact holes for said source region and said channel region as well as for said connecting gate trench, and to finally structure said gate contacts and said source contact. Thus, a flexible layout concept is possible in which said gate contact can also be placed in the middle of or at another location on said power MOS element without additional expenditure. Optionally, without additional process steps, margin terminating structures can be produced parallel to the formation of said active transistor region in the form of circumferential floating rings or of floating field plates.
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Citations
42 Claims
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1. Power MOS element comprising:
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a drift region with a doping of a first doping type;
a channel region with a doping of a second doping type, said second doping type being complementary to said first doping type, and said channel region bordering on said drift region;
a source region with a doping of said first doping type, said source region bordering on said channel region;
a plurality of essentially parallel gate trenches spaced from one another defining an active region of said power MOS element and extending through said source region, said channel region and into said drift region, said gate trenches comprising an electrically conductive material which is electrically insulated from said source region, said channel region and said drift region by an insulator;
a connecting gate trench for connecting the gate trenches in an electrically conductive way, extending through said source region, said channel region and into said drift region, said connecting gate trench comprising an electrically conductive material which is electrically insulated from said source region, said channel region and said drift region by an insulator, said connecting gate trench being a circumferential trench comprising a first connecting region, a second connecting region, a first longitudinal region and a second longitudinal region, said first connecting region connecting first ends of said plurality of gate trenches to one another, said second connecting region connecting second ends of said plurality of gate trenches to one another, and said first and said second longitudinal regions connecting said first and said second connecting regions to each other in such a way that the active region which is defined by said plurality of gate trenches is completely surrounded by said connecting gate trench;
a source contact structure for contacting said source region;
a channel contact structure for contacting said channel region;
a gate contact for contacting said connecting gate trench, said gate contact being connected via a contact hole through said insulator of said connecting gate trench which is filled with an electrically conductive material to said electrically conductive material of said connecting gate trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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12. Power MOS element comprising:
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a drift region with a doping of a first doping type;
a channel region with a doping of a second doping type, said second doping type being complementary to said first doping type, and said channel region bordering on said drift region;
a source region with a doping of said first doping type, said source region bordering on said channel region;
a plurality of essentially parallel gate trenches spaced from one another defining an active region of the power MOS element and extending through said source region, said channel region and into said drift region, said gate trenches comprising an electrically conductive material which is electrically insulated from said source region, said channel region and said drift region by an insulator;
a connecting gate trench for connecting the gate trenches in an electrically conductive way, extending through said source region, said channel region and into said drift region, said connecting gate trench comprising an electrically conductive material which is electrically insulated from said source region, said channel region and said drift region by an insulator, said connecting gate trench comprising a circumferential section surrounding a non-active region of said power MOS element, in which there are no gate trenches, and extension sections connected in an electrically conductive way to said circumferential section, said extension sections connecting at least a part of the gate trenches to one another in an electrically conductive way;
a source contact structure for contacting said source region;
a channel contact structure for contacting aid channel region;
a gate contact for contacting said connecting gate trench, said gate contact being connected via a contact hole through said insulator of said connecting gate trench which is filled with an electrically conductive material to said electrically conductive material of said connecting gate trench.
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25. Method for producing a power MOS element, comprising the following steps:
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providing a substrate having a drift region with a doping of a first doping type, a channel region with a doping of a second doping type, said second doping type being complementary to said first doping type and said channel region bordering on said drift region, and a source region with a doping of said first doping type, said source region bordering on said channel region;
photolithographic producing of essentially parallel gate trenches spaced from one another defining an active region of the power MOS element, and of a connecting gate trench by means of which said plurality of essentially parallel gate trenches is connectable to one another in an electrically conductive way in such a way that said gate trenches extend through said source region, said channel region and into said drift region, wherein said connecting gate trench being a circumferential trench comprising a first connecting region, a second connecting region, a first longitudinal region and a second longitudinal region, said first connecting region connecting first ends of said plurality of gate trenches to one another, said second connecting gate trench connecting second ends of said plurality of gate trenches to one another, and said first and said second longitudinal regions connecting said first and said second connecting regions to one another in such a way that the active region which is defined by said plurality of gate trenches is completely surrounded by said connecting gate trench;
orwherein said connecting gate trench comprising a circumferential section surrounding a non-active region of said power MOS element, in which there are no gate trenches, and extension sections being connected to said circumferential section in an electrically conductive way, said extension sections connecting at least a part of said gate trenches to one another in an electrically conductive way;
processing said gate trenches and said connecting gate trench in order to comprise a conductive material which is isolated from said source region, said channel region and said drift region by an insulator;
photolithographic producing of contact holes for contacting said source region, said channel region and said connecting gate trench, said connecting gate trench being contactable via said contact holes associated to said connecting gate trench;
filling said contact holes with an electrically conductive material; and
photolithographic producing of said gate contact, said source contact and said channel contact.
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Specification