Field effect transistor and fabrication method
AssigneeInfineon Technologies AG
InventorsKarlheinz Muller, Klaus Roschlau
Life of this patent
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Abstract
A field effect transistor (FET) and fabrication method are disclosed. The FET includes a drift region formed in a substrate. A trench adjoins the drift region and contains at least one control region and a connection region. An inversion channel region is isolated from the control region. A portion of the trench extends to the same depth as a second trench that insulates the FET from other components formed in the substrate. Insulating material is disposed between the trench below the control region and the control region. An insulating layer insulates the FET from the substrate. The trench and/or the connection region may extend into the insulating layer or may be isolated from the insulating layer via the drift region.
Claims24
A field effect transistor comprising:
- a substrate;
- a drift region formed in the substrate;
- a first trench adjoining the drift region;
- a control region disposed in the first trench;
- a first connection region disposed in the first trench and a second connection region disposed outside the first trench;
- and
- an inversion channel region isolated from the control region via a dielectric,
- wherein at least a portion of the first trench extends to the same depth as a second trench that insulates the field effect transistor from other components formed in the substrate.
A field effect transistor comprising:
- a substrate;
- a drift region formed in the substrate and doped with a first doping type;
- a first trench adjoining the drift region;
- a first control region disposed in the first trench and doped with the first doping type;
- a first connection region disposed in the first trench and a second connection region disposed outside the first trench, the first and second connection regions doped with the first doping type, the first connection region doped more heavily than the drift region;
- and
- an inversion channel region isolated from the first control region via a dielectric, the inversion channel region doped with a second doping type,
- wherein at least a portion of the first trench extends to the same depth as a second trench that insulates the field effect transistor from other components formed in the substrate, and
- wherein at least one of:
- a second control region is disposed in the first trench, or
- the first trench forms a ring, the first control region being ring-shaped and surrounding the first connection region.
A method for fabricating a field effect transistor, the method comprising the following implemented without any restriction by the order specified:
- forming a trench in a drift region of a substrate;
- filling the trench with an insulating material;
- patterning the insulating material to produce a first cutout for a control region and a second cutout for a first connection region, the first and second cutouts isolated by the insulating material, the first connection region being connected to the drift region;
- providing an electrically conductive material in the first and second cutouts;
- and
- forming a second connection region outside the trench before or after forming the trench, and an inversion channel region before or after forming the trench.
A method for fabricating a field effect transistor, the method comprising the following implemented without any restriction by the order specified:
- forming a trench in a drift region of a substrate;
- filling the trench with an insulating material;
- patterning the insulating material to produce a first cutout for a first control region and a second cutout for a first connection region, the first and second cutouts isolated by the insulating material, the first connection region being connected to the drift region;
- providing an electrically conductive material in the first and second cutouts;
- forming a second connection region outside the trench before or after forming the trench, and an inversion channel region before or after forming the trench;
- and
- at least one of:
- forming a second control region in the trench, or
- forming the trench in a ring, the first control region being ring-shaped and surrounding the first connection region.
A field effect transistor comprising:
- a substrate;
- a drift region formed in the substrate;
- means for controlling the field effect transistor;
- means for connecting to the drift region;
- means for forming an inversion channel;
- means for isolating the controlling means and the connecting means from the means for forming the inversion region;
- and
- means for insulating the field effect transistor from other components formed in the substrate.
Dependencies are inferred from the claim text.