Method of forming trench gate field effect transistor with recessed mesas
First Claim
1. A method of forming a field effect transistor comprising an active area and a termination region surrounding the active area, the method comprising:
- forming gate trenches extending into a silicon region of a first conductivity type;
forming a well region of a second conductivity type in the silicon region;
forming a recessed gate in each gate trench;
forming a dielectric cap over each gate;
recessing all exposed surfaces of the well region to form a recess in the well region between every two adjacent trenches such that the recess has sloped walls and a bottom located between a top surface of the dielectric cap and a top surface of the recessed gate; and
without masking any portion of the active area, performing a zero-degree blanket implant to form a heavy body region of the second conductivity type in the well region between every two adjacent trenches whereby the heavy body region is self-aligned to the gate trenches.
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Accused Products
Abstract
A monolithically integrated field effect transistor and Schottky diode includes gate trenches extending into a semiconductor region. Source regions having a substantially triangular shape flank each side of the gate trenches. A contact opening extends into the semiconductor region between adjacent gate trenches. A conductor layer fills the contact opening to electrically contact: (a) the source regions along at least a portion of a slanted sidewall of each source region, and (b) the semiconductor region along a bottom portion of the contact opening, wherein the conductor layer forms a Schottky contact with the semiconductor region.
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Citations
13 Claims
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1. A method of forming a field effect transistor comprising an active area and a termination region surrounding the active area, the method comprising:
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forming gate trenches extending into a silicon region of a first conductivity type; forming a well region of a second conductivity type in the silicon region; forming a recessed gate in each gate trench; forming a dielectric cap over each gate; recessing all exposed surfaces of the well region to form a recess in the well region between every two adjacent trenches such that the recess has sloped walls and a bottom located between a top surface of the dielectric cap and a top surface of the recessed gate; and without masking any portion of the active area, performing a zero-degree blanket implant to form a heavy body region of the second conductivity type in the well region between every two adjacent trenches whereby the heavy body region is self-aligned to the gate trenches. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification