SEMICONDUCTOR DEVICE
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Abstract
In a JBS diode using a wide band gap semiconductor, the wide band gap semiconductor has a large built-in voltage, which sometimes causes difficulties for the pn diode portion to turn on, resulting in a problem that resistance to surge currents is not sufficiently ensured. In order to solve this problem, in the wide-band-gap JBS diode, a pn junction of the pn diode is formed away from the Schottky electrode, and well regions are formed so as to have a width narrowed at a portion away from the Schottky electrode.
24 Citations
29 Claims
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1-10. -10. (canceled)
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11. A semiconductor device comprising:
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a wide band gap semiconductor substrate that is of a first conductive type; a drift layer that is of the first conductive type and configured with a wide band gap semiconductor and that is formed on a first main surface of the wide band gap semiconductor substrate; a plurality of first well regions that are of a second conductive type and that are formed in a surface layer portion of the drift layer adjacent to each other at a predetermined interval; a second well region that is formed adjacent to each of the first well regions and toward the semiconductor substrate, has a second conductive type impurity density lower than the first well regions, and has a width narrower than the first well regions; a Schottky electrode that is formed on surfaces of the drift layer and the first well regions to form a Schottky connection with the drift layer; and an ohmic electrode that is formed on a second main surface of the semiconductor substrate which is opposite to the first main surface, wherein when the semiconductor device is in an off-state, there remain regions that are not depleted in the first well regions. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A semiconductor device comprising:
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a wide band gap semiconductor substrate that is of a first conductive type; a drift layer that is of the first conductive type and configured with a wide band gap semiconductor and that is formed on a first main surface of the wide band gap semiconductor substrate; a plurality of first well regions that are of a second conductive type and that are formed in a surface layer portion of the drift layer adjacent to each other at a predetermined interval; a second well region that is formed adjacent to each of the first well regions and toward the semiconductor substrate, has a second conductive type impurity density lower than the first well regions, and has a width narrower than the first well regions; a Schottky electrode that is formed on surfaces of the drift layer and the first well regions to form a Schottky connection with the drift layer; and an ohmic electrode that is formed on a second main surface of the semiconductor substrate which is opposite to the first main surface, wherein when the semiconductor device is in an off-state, the second well region is entirely depleted. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A semiconductor device comprising:
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a wide band gap semiconductor substrate that is of a first conductive type; a drift layer that is of the first conductive type and configured with a wide band gap semiconductor and that is formed on a first main surface of the wide band gap semiconductor substrate; a plurality of first well regions that are of a second conductive type and that are formed in a surface layer portion of the drift layer adjacent to each other at a predetermined interval; a second well region that is formed adjacent to each of the first well regions and toward the semiconductor substrate, has a second conductive type impurity density lower than the first well regions, and has a width narrower than the first well regions; a Schottky electrode that is formed on surfaces of the drift layer and the first well regions to form a Schottky connection with the drift layer; and an ohmic electrode that is formed on a second main surface of the semiconductor substrate which is opposite to the first main surface, wherein the width of the second well region is three fourths or less of the width of each of the first well regions. - View Dependent Claims (26, 27, 28, 29)
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Specification