Manufacture of trench-gate semiconductor devices
First Claim
1. A method of manufacturing a trench-gate semiconductor device having source and drain regions of a first conductivity type which are separated by a channel-accommodating region adjacent to the trench-gate, including the steps of:
- (a) forming at a surface of a semiconductor body a first mask having a first window at an area of the body,(b) forming the source region by introducing dopant of the first conductivity type into the said area via the first window,(c) forming on the body a second mask having a second window smaller than the first window by providing sidewall extensions on the first mask at the first window,(d) etching a trench into the body at the second window to extend through a body region and into an underlying portion of the drain region,(e) depositing material in the trench to provide the gate adjacent to where the channel is accommodated in the body, and(f) providing a source electrode on the body after removing the second mask so as to expose the source region and an adjacent surface region of the body for contacting by the source electrode.
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Accused Products
Abstract
The manufacture of a trench-gate semiconductor device, for example a MOSFET or IGBT, includes the steps of forming at a surface (10a) of a semiconductor body (10) a first mask (51) having a first window (51a), and later forming a second mask (52) having a smaller window (52a) by providing sidewall extensions (52b) on the first mask (51). A source region (13) is formed by dopant (63) introduced via the first window (51a), whereas a trench (20) is etched at the smaller window (52a) to extend through a body region (15) and into an underlying portion of a drain region (14). The gate (11) is provided in the trench (20) adjacent to where the channel (12) of the device is accommodated. After removing the second mask (52), a source electrode (23) is provided to contact the source region (13) and an adjacent region (15) of the body (10) at the surface (10a). This method permits the use of self-aligned masking techniques while providing good reproduceability in the doping of the source region (13) and adjacent region (15) and in the contact area of the source electrode (23) with both the source region (13) and the adjacent region (15).
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Citations
10 Claims
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1. A method of manufacturing a trench-gate semiconductor device having source and drain regions of a first conductivity type which are separated by a channel-accommodating region adjacent to the trench-gate, including the steps of:
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(a) forming at a surface of a semiconductor body a first mask having a first window at an area of the body, (b) forming the source region by introducing dopant of the first conductivity type into the said area via the first window, (c) forming on the body a second mask having a second window smaller than the first window by providing sidewall extensions on the first mask at the first window, (d) etching a trench into the body at the second window to extend through a body region and into an underlying portion of the drain region, (e) depositing material in the trench to provide the gate adjacent to where the channel is accommodated in the body, and (f) providing a source electrode on the body after removing the second mask so as to expose the source region and an adjacent surface region of the body for contacting by the source electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification