Method of forming trench gate field effect transistor with recessed mesas
AssigneeFairchild Semiconductor Corporation
InventorsSteven Sapp, Hamza Yilmaz, Christopher Lawrence Rexer, Daniel Calafut
Life of this patent
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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.
Claims13
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.
Dependencies are inferred from the claim text.