Method of manufacturing a trench MOSFET using selective growth epitaxy
AssigneeFairchild Semiconductor Corporation
InventorGordon K. Madson
Life of this patent
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Abstract
A method of manufacturing a trench structure for a trench MOSFET, including the steps of providing a semiconductor substrate having a major surface, forming a dielectric pillar on the substrate major surface (the dielectric pillar extending substantially perpendicularly from the major surface of the substrate), selectively forming a semiconductor layer around the dielectric pillar, and removing a predetermined length of the dielectric pillar to create a trench in the substrate, the trench defined by sidewalls and a bottom. The method permits the controlled formation of a dielectric plug at the bottom of the trench, the plug having predetermined dimensions.
Claims21
A method of forming a trench structure, the method comprising the steps of:
- providing a semiconductor substrate having a major surface;
- forming a dielectric pillar on the substrate major surface, the dielectric pillar extending substantially perpendicularly from the major surface;
- selectively forming a semiconductor layer around the dielectric pillar;
- and
- removing a predetermined first portion of the dielectric pillar to create a trench in the substrate, the trench defined by sidewalls and a bottom,
- wherein a second portion of the dielectric pillar having a predetermined thickness is left at the bottom of the trench following the step of removing a predetermined first portion of the dielectric pillar.
A method of manufacturing a trench field effect transistor, comprising the steps of:
- providing a semiconductor substrate having a major surface and a first conductivity type;
- forming a plurality of dielectric columns extending perpendicularly from the major surface of the substrate;
- selectively forming a first semiconductor layer having the first conductivity type over exposed areas of the major surface of the substrate and around the dielectric columns;
- selectively forming a second semiconductor layer having a second conductivity type, opposite to that of the first conductivity type, over the first semiconductor layer and around the dielectric columns;
- selectively forming a third semiconductor layer having the first conductivity type over the second semiconductor layer and around the semiconductor columns;
- removing a predetermined portion of each dielectric column to create a plurality of trenches extending through the third, second and a portion of the first semiconductor layer, each trench defined by a bottom and sidewalls, wherein a second portion of each dielectric column having a predetermined thickness is left at the bottom of each trench;
- and
- lining the sidewalk of the trenches with a gate oxide.
Dependencies are inferred from the claim text.