Vertical MOSFET having a high resistance region
AssigneeFuji Electric Co., Ltd.
InventorKatsunori Ueno
Life of this patent
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Abstract
A vertical MOSFET having a compound semiconductor layer is provided, the vertical MOSFET comprising a gate electrode, a gate insulating film provided between the gate electrode and the compound semiconductor layer, a drift region provided directly in contact with at least a part of the gate insulating film and being a part of the compound semiconductor layer, and a high resistance region provided at least in the drift region, is positioned below at least a part of the gate insulating film, and has a higher resistance value per unit length than that of the drift region.
Claims11
A vertical MOSFET having a compound semiconductor layer, the vertical MOSFET comprising:
- a gate electrode;
- a gate insulating film which is provided between the gate electrode and the compound semiconductor layer;
- a drift region which is provided directly in contact with at least a part of the gate insulating film and is a part of the compound semiconductor layer;
- and
- a high resistance region which is provided at least in the drift region, is positioned below at least the part of the gate insulating film, and has a higher resistance value per unit length than that of the drift region, wherein
- the gate electrode is a trench type gate electrode which is embedded in a trench portion that is provided in the compound semiconductor layer,
- the high resistance region is adjacent to a bottom portion of the trench portion,
- the high resistance region is spaced from the gate insulating film and below at least the part of the gate insulating film,
- a width of the high resistance region is wider than a width of the trench portion,
- the high resistance region has a resistance value of equal to or more than 10 Ω·cm per unit length, and
- the compound semiconductor layer is a gallium nitride layer.
A vertical MOSFET having a gallium nitride layer, the vertical MOSFET comprising:
- a gate electrode;
- a gate insulating film which is provided between the gate electrode and the gallium nitride layer;
- a drift region which is provided directly in contact with at least a part of the gate insulating film and is a part of the gallium nitride layer;
- and
- a high resistance region which is provided at least in the drift region, is positioned below at least the part of the gate insulating film, and has a higher resistance value per unit length than that of the drift region and is a part of the gallium nitride layer, wherein
- the gate electrode is a trench type gate electrode which is embedded in a trench portion that is provided in the gallium nitride layer,
- the high resistance region is adjacent to a bottom portion of the trench portion,
- a width of the high resistance region is wider than a width of the trench portion,
- the high resistance region has a resistance value of equal to or more than 10 Ωcm per unit length,
- the high resistance region has a resistance-increasing element with a concentration of equal to or more than 1E+16 cm−3 and equal to or less than 1E+19 cm−3,
- the high resistance region is formed by annealing at a temperature of equal to or more than 1000° C. and equal to or less than 1300° C. after implantation of the resistance-increasing element, the annealing performed before the gate insulating film is provided,
- the resistance-increasing element is one or more of magnesium, argon, and nitrogen,
- the high resistance region is provided separate from the bottom portion of the trench portion and below the bottom portion, and has electrical characteristics of an insulator, and
- sides of the trench portion are mainly in contact with a base region.
Dependencies are inferred from the claim text.