Method for fabricating NROM memory cells with trench transistors
First Claim
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1. A method of forming a semiconductor device, the method comprising:
- providing a semiconductor body that is doped to a first conductivity type;
doping an upper portion of the semiconductor body to a second conductivity type;
forming conductive lines over the semiconductor body;
etching a recess in the semiconductor body between the conductive lines, the recess extending through the upper portion of the semiconductor body;
forming a storage layer in the recess; and
forming a conductor over the storage layer and within the recess.
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Abstract
An electrically conductive bit line layer is applied and patterned into portions arranged parallel to one another before the trench is etched into the semiconductor material, in which case, after the patterning of the bit line layer (3, 4) and before the etching of the trench, an implantation is introduced for the purpose of defining the position of the junctions, or, after the implantation of the n+-type well (19) for the source/drain regions, the bit line layer (3, 4) is patterned using an etching stop layer (2) arranged on the semiconductor body (1).
15 Citations
26 Claims
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1. A method of forming a semiconductor device, the method comprising:
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providing a semiconductor body that is doped to a first conductivity type;
doping an upper portion of the semiconductor body to a second conductivity type;
forming conductive lines over the semiconductor body;
etching a recess in the semiconductor body between the conductive lines, the recess extending through the upper portion of the semiconductor body;
forming a storage layer in the recess; and
forming a conductor over the storage layer and within the recess. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for fabricating a semiconductor device that includes a plurality of NROM memory cells, the semiconductor device comprising:
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a gate electrode, which is arranged at a top side of a semiconductor body or a semiconductor layer and is isolated from the semiconductor material by dielectric material; and
a source region and a drain region, which are formed in the semiconductor material;
the gate electrode being arranged in a trench formed in the semiconductor material between the source region and the drain region; and
a storage layer being present at least between the source region and the gate electrode and between the drain region and the gate electrode, which storage layer is provided for trapping charge carriers;
the method comprising;
applying at least one electrically conductive bit line layer over the semiconductor body or semiconductor layer;
patterning the at least one electrically conductive bit line layer into portions that are arranged parallel to one another;
etching the trench into the semiconductor material from a top side of the semiconductor layer between said portions; and
after patterning the at least one electrically conductive bit line layer and before the etching of the trench, introducing an implantation to define a position at which a boundary between a source/drain region and a channel region provided at a lower portion of the trench adjoins the trench. - View Dependent Claims (18, 19, 20, 21)
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22. A method for fabricating a semiconductor device that includes a plurality of NROM memory cells, the semiconductor device comprising:
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a gate electrode, which is arranged at a top side of a semiconductor body or a semiconductor layer and is isolated from the semiconductor material by dielectric material; and
a source region and a drain region, which are formed in the semiconductor material;
the gate electrode being arranged in a trench formed in the semiconductor material between the source region and the drain region; and
a storage layer being present at least between the source region and the gate electrode and between the drain region and the gate electrode, which storage layer is provided for trapping charge carriers;
the method comprising;
implanting source/drain regions in the semiconductor body;
applying an etch stop layer over the semiconductor body;
applying at least one electrically conductive bit line layer over the semiconductor body;
patterning the at least one electrically conductive bit line layer into portions that are arranged parallel to one another, the at least one electrically conductive bit line layer using the etch stop layer after implanting the source/drain regions; and
etching the trench into the semiconductor material from a top side of the semiconductor layer between said portions. - View Dependent Claims (23, 24, 25, 26)
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Specification