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US 9,960,234 B2Granted
Method of forming a semiconductor device and structure therefor
AssigneeSemiconductor Components Industries, LLC
InventorsKirk Huang, Chun-Li Liu, Ali Salih
Life of this patent
Estimating the term…
Abstract
In one embodiment, a method of forming an MOS transistor includes forming a threshold voltage (Vth) of the MOS transistor to have a first value at interior portions of the MOS transistor and a second value at other locations within the MOS transistor that are distal from the interior portion wherein the second value is less than the first value.
Claims17
An semiconductor device comprising:
- an MOS transistor formed as a plurality of transistor cells on a semiconductor substrate;
- a body region of a first cell of the plurality of transistor cells formed as a first doped region having a first conductivity type;
- a source region of the first cell formed as a second doped region within the first doped region, the second doped region having a second conductivity type;
- a gate structure formed adjacent to the source region and a portion of the body region, the gate structure having an internal gate conductor that is connected to an external gate conductor that overlies the semiconductor substrate and is external to the gate structure;
- and
- the first doped region having a width and a length and a depth wherein the length is greater than the width and greater than the depth wherein a direction of the width is substantially orthogonal to a direction of the length, and a direction of the depth is substantially orthogonal to the direction of both the length and width, the length extends substantially laterally along a side of the gate structure and in a direction away from the external gate conductor toward an interior of the body region, the first doped region having a first end proximal to the external gate conductor and also having a second end that is spaced the length away from the first end with the interior of the first doped region positioned along the length and distal from the first and second ends, a midpoint of the length positioned approximately at a midpoint between the first and second ends, the first doped region including dopants wherein a doping concentration of the dopants of the first doped region is formed to increase laterally along the length of the first doped region toward the interior of the first doped region with increasing distance from the external gate conductor wherein the doping concentration at substantially the midpoint of the length is greater than at approximately a quarter of a distance between the first end and the midpoint, and the doping concentration is lower at the first and second ends than at the quarter of the distance.
3 more elements
A semiconductor device comprising:
- an MOS transistor formed as a plurality of transistor cells on a semiconductor substrate, the MOS transistor having an MOS gate, an MOS source, and an MOS drain;
- a first transistor formed as a heterojunction transistor, the first transistor having a first gate, a first source, and a first drain;
- the MOS transistor coupled in a cascode configuration with the first transistor;
- and
- back-to-back diodes in a series configuration between the MOS gate and the MOS drain wherein one of the back-to-back diodes is directly connected to the MOS drain and wherein the back-to-back diodes have anodes connected directly together.
2 more elements
A semiconductor device comprising:
- an MOS transistor formed as a plurality of transistor cells on a semiconductor substrate;
- a body region of a first cell of the plurality of transistor cells formed as a first doped region having a width and a length and a depth wherein the length is greater than the width, the first doped region having a first conductivity type;
- a source region of the first cell formed as a second doped region within the first doped region, the second doped region having a second conductivity type;
- a gate structure formed adjacent to the source region and a portion of the body region, the gate structure having an internal gate conductor that is connected to an external gate conductor that overlies the semiconductor substrate and is external to the gate structure;
- and
- the first doped region including dopants wherein a doping concentration of the dopants of the first doped region is formed to increase laterally along the length of the first doped region toward interior portions of the first doped region with increasing distance from the external gate conductor wherein the first doped region has a first end and has a second end that is spaced the length from the first end with an interior of the first doped region positioned distal from the first and second ends and in a plane of the first and second ends, wherein the doping concentration at the interior is twice the doping concentration at the first end and the doping concentration of the first doped region increases with distance from the first end toward the interior.
3 more elements
Dependencies are inferred from the claim text.