High voltage transistors and thyristors
AssigneeIXYS Corporation
InventorNathan Zommer
Life of this patent
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Abstract
A high voltage transistor or thyristor having a base layer which is a thinned neutron transmuted wafer 102, 152 instead of a diffused or epitaxially grown base layer. The neutron transmuted wafer has high resistivity and a desired thickness while the layer formed overlying the surface of the neutron transmuted wafer has a desired thickness and doping level. Adjusting the thicknesses and doping levels within these two structures produce a device having the desire high voltage characteristics. The various embodiments provides for a high voltage MOSFET 100, IGBT 170, and thyristor.
Claims10
A method of fabricating a high voltage MOS switching device comprising:
- providing a semiconductor substrate having a backside and a front surface, said semiconductor substrate being a resistive semiconductor substrate;
- forming a semiconductor layer directly on and in contact with said front surface of the substrate, said semiconductor layer being a heavily doped epitaxial layer of low resistivity relative to said semiconductor substrate to achieve a desired growth rate and capability of operating in high power applications;
- reducing a thickness of said substrate from said backside;
- turning said substrate up-side-down;
- and
- forming a plurality of active MOS devices on said backside,
- wherein said semiconductor layer and said substrate are adjusted to produce a desired breakdown voltage characteristic, said device having a breakdown voltage greater than about 1000 volts.
Dependencies are inferred from the claim text.