SELF-ALIGNED BODY CONTACT FOR A SEMICONDCUTOR-ON-INSULATOR TRENCH DEVICE AND METHOD OF FABRICATING SAME
First Claim
1. A method of forming a contact;
- comprising;
forming set of mandrels on a top surface of a substrate, each mandrel of said set of mandrels arranged on a different corner of a polygon and extending above said top surface of said substrate, a number of mandrels in said set of mandrels equal to a number of corners of said polygon;
forming sidewall spacers on sidewalls of each mandrel of said set of mandrels, sidewalls spacers of each adjacent pair of mandrels merging with each other and forming a unbroken wall defining an opening in an interior region of said polygon, a region of said substrate exposed in said opening;
etching a contact trench in said substrate in said opening; and
filling said contact trench with an electrically conductive material to form said contact.
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Accused Products
Abstract
A structure and method of forming a body contact for an semiconductor-on-insulator trench device. The method including: forming set of mandrels on a top surface of a substrate, each mandrel of the set of mandrels arranged on a different corner of a polygon and extending above the top surface of the substrate, a number of mandrels in the set of mandrels equal to a number of corners of the polygon; forming sidewall spacers on sidewalls of each mandrel of the set of mandrels, sidewalls spacers of each adjacent pair of mandrels merging with each other and forming a unbroken wall defining an opening in an interior region of the polygon, a region of the substrate exposed in the opening; etching a contact trench in the substrate in the opening; and filling the contact trench with an electrically conductive material to form the contact.
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Citations
30 Claims
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1. A method of forming a contact;
- comprising;
forming set of mandrels on a top surface of a substrate, each mandrel of said set of mandrels arranged on a different corner of a polygon and extending above said top surface of said substrate, a number of mandrels in said set of mandrels equal to a number of corners of said polygon;
forming sidewall spacers on sidewalls of each mandrel of said set of mandrels, sidewalls spacers of each adjacent pair of mandrels merging with each other and forming a unbroken wall defining an opening in an interior region of said polygon, a region of said substrate exposed in said opening;
etching a contact trench in said substrate in said opening; and
filling said contact trench with an electrically conductive material to form said contact. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 11)
- comprising;
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9. The method of claim 9, further including:
forming a buried electrically conductive strap between said first source or drain of said vertical NFET or said vertical PFET and a plate of said trench capacitor, said plate formed inside said device trench.
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12. A method of forming a dynamic access memory cell, comprising:
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forming a pad layer on a top surface of a semiconductor-on-insulator substrate, said substrate including a buried insulating layer separating said substrate into an upper semiconductor layer between a top surface of said buried insulating layer and said top surface of substrate and a lower semiconductor layer;
forming a set of device trenches, each device trench extending from a top surface of said pad layer, through said upper semiconductor layer, through said buried insulating layer and into said lower semiconductor layer;
forming a dielectric layer on sidewalls of said device trenches and filling said device trenches with an electrically conductive first fill material to a level below said a top surface of said buried insulating layer to form a trench capacitor;
forming a buried electrically conductive strap around each of said devices trenches in said buried insulating layer and forming sources or drains in said upper semiconductor layer adjacent to said buried strap;
forming a first insulating cap over said first fill material;
forming a gate dielectric on sidewalls of said device trenches above said first fill material;
filling said device trenches with an electrically conductive second fill material to form vertical gates;
removing said pad layer to expose mandrels comprising regions of said vertical gates extending above said top surface of said substrate;
forming sidewall spacers on sidewalls of said mandrels, said sidewall spacers merging with each other and forming an unbroken ring around a region of said substrate;
etching a contact trench through said upper semiconductor layer, said buried insulating layer and into said lower semiconductor layer in said region of said substrate not covered by said sidewall spacers;
filling said contact trench with an electrically conductive third fill material and recessing said third fill material below said top surface of said substrate but above said top surface of said buried insulating layer;
forming in said contact trench, a second insulating cap over said third fill material and forming an electrically conductive cap over said second insulating cap; and
removing said sidewall spacers and forming sources or drains in said upper semiconductor layer around said device trenches adjacent to said top surface of said upper semiconductor layer. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. An electronic device, comprising:
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a semiconductor on insulator substrate, said substrate including a buried insulating layer separating said substrate into an upper semiconductor layer between a top surface of said buried insulating layer and said top surface of substrate and a lower semiconductor layer;
at least three vertical field effect transistors (FETs), each of said three or more FETs having a body formed in said upper semiconductor layer, a gate extending from said top surface of said substrate, a first source/drain formed around said gate adjacent to said top surface of said upper semiconductor layer and a second source drain formed around said gate adjacent to said buried insulating layer; and
a body contact formed in said substrate between said at least three vertical FETs, said body contact self-aligned to all of said gates of said at least three vertical FETs, said body contact extending above and below said buried insulating layer and electrically connecting said upper semiconductor layer to said lower semiconductor layer. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification