The semiconductor device includes: a substrate, an n-type drift region formed on a main surface of the substrate; a p-type well region, an n-type drain region and an n-type source region each formed in the drift region to extend from a second main surface of the drift region opposite to the first main surface of the drift region in contact with the substrate in a direction perpendicular to the second main surface; a gate groove extending from the second main surface in the perpendicular direction and penetrating the source region and the well region in a direction parallel to the first main surface of the substrate; and a gate electrode formed on a surface of the gate groove with a gate insulating film interposed therebetween, wherein the drift region has a higher impurity concentration than the substrate, and the well region extends to the inside of the substrate.

A semiconductor device includes a semiconductor substrate with a trench, a body region under the trench with majority carrier dopants of a first type, and a transistor, including a source region under the trench with majority carrier dopants of a second type, a drain region spaced from the trench with majority carrier dopants of the second type, a gate structure in the trench proximate a channel portion of a body region, and an oxide structure in the trench proximate a side of the gate structure.

The method comprises forming a drain region in the first layer. The drain region is formed comprising a drain rectangular portion having a first end and a second end, a first drain end portion contiguous with the drain rectangular portion and extending from the first end of the drain rectangular portion away from a center of the drain region, and a second drain end portion contiguous with the drain rectangular portion and extending from the second end of the drain rectangular portion away from the center of the drain region. The method also comprises forming a source region free from contact with and surrounding the drain region in the first layer.

In some examples, a semiconductor device, comprises a semiconductor substrate; an epitaxial layer having a top side disposed on the semiconductor substrate, wherein the epitaxial layer has a source implant region, a drain implant region, a first doped region, and a second doped region, wherein the first doped region is adjacent to the source implant region and the second doped region is adjacent to the drain implant region, wherein the top side has a sloped surface over the second doped region; a gate electrode supported by the top side; a source electrode in contact with the source implant region; and a drain electrode in contact with the drain implant region.

A semiconductor structure that includes at least one lateral diffusion field effect transistor is described. The structure includes a source contact and a gate shield that enables the line width of an ohmic region that electrically connects the source/body region to the gate shield to be smaller than the minimum contact feature size. The gate shield defines a bottom recess for forming a narrower bottom portion of the source contact, and a section that flares outward with distance from the ohmic region to extend above and laterally beyond the ohmic region. By providing a wider area for the source contact, the flared portion of the gate shield allows the portion of the gate shield that contacts the ohmic region to be narrower than the minimum contact feature size. As a result, the cell pitch of the lateral diffusion field effect transistor can be reduced.

A MOSFET structure and a manufacturing method thereof are provided. The structure includes a substrate, a well region of a first conductivity type, a first trench formed on a surface of the well region of the first conductivity type and extending downwards to a well region of a second conductivity type, a source disposed in the well region of the second conductivity type and under the first trench, a gate oxide layer disposed on an inner surface of the first trench, a polysilicon gate disposed on the gate oxide layer, a conductive plug extending downwards from above the first trench and being in contact with the well region of the second conductivity type after extending through the source, an insulation oxide layer filled in the first trench between the conductive plug and the polysilicon gate, and a drain disposed outside the first trench and obliquely above the source.

A semiconductor device includes a semiconductor substrate with a trench, a body region under the trench with majority carrier dopants of a first type, and a transistor, including a source region under the trench with majority carrier dopants of a second type, a drain region spaced from the trench with majority carrier dopants of the second type, a gate structure in the trench proximate a channel portion of a body region, and an oxide structure in the trench proximate a side of the gate structure.

A planar gate power MOSFET includes a substrate having a semiconductor surface doped a first conductivity type, a plurality of transistor cells (cells) including a first cell and at least a second cell each having a gate stack over a body region. A trench has an aspect ratio of >3 extending down from a top side of the semiconductor surface between the gate stacks providing a source contact (SCT) from a source doped a second conductivity type to the substrate. A field plate (FP) is over the gate stacks that provides a liner for the trench. The trench has a refractory metal or platinum-group metal (PGM) metal filler within. A drain doped the second conductivity type is in the semiconductor surface on a side of the gate stacks opposite the trench.

A semiconductor device includes a first transistor and a second transistor in a semiconductor substrate. The first transistor includes a first drain contact electrically connected to a first drain region, the first drain contact including a first drain contact portion and a second drain contact portion. The first drain contact portion includes a drain conductive material in direct contact with the first drain region. The second transistor includes a second source contact electrically connected to a second source region. The second source contact includes a first source contact portion and a second source contact portion. The first source contact portion includes a source conductive material in direct contact with the second source region.

Implementations of the present disclosure generally relate to methods for forming a transistor. More specifically, implementations described herein generally relate to methods for forming a source/drain contact. In one implementation, the method includes forming a trench in a dielectric material to expose a source/drain region of a transistor, performing a pre-clean process on the exposed source/drain region, forming a doped semiconductor layer on the source/drain region by an epitaxial deposition process, and fill the trench with a conductor. The doped semiconductor layer has a lower electrical resistance than the source/drain region due to a higher dopant concentration in the doped semiconductor layer. As a result, the contact resistance of the source/drain contact is reduced.