Reduced process sensitivity of electrode-semiconductor rectifiers
First Claim
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1. A semiconductor device, comprising:
- a semiconductor layer;
a trench disposed in the semiconductor layer;
a first electrode disposed in the trench;
a mesa region adjacent to the trench and being defined, at least in part, by the trench, the mesa region having a top surface and a graded region, the graded region having a doping concentration decreasing with increasing depth from the top surface of the mesa region, the doping concentration of the graded region being highest at the top surface of the mesa region, the first electrode having at least a portion electrically insulated from the mesa region; and
a second electrode disposed on the top surface of the mesa region, the second electrode being a first portion of a Schottky contact, the top surface of the mesa region being a second portion of the Schottky contact.
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Abstract
Disclosed are semiconductor devices and methods of making semiconductor devices. An exemplary embodiment comprises a semiconductor layer of a first conductivity type having a first surface, a second surface, and a graded net doping concentration of the first conductivity type within a portion of the semiconductor layer. The graded portion is located adjacent to the top surface of the semiconductor layer, and the graded net doping concentration therein decreasing in value with distance from the top surface of the semiconductor layer. The exemplary device also comprises an electrode disposed at the first surface of the semiconductor layer and adjacent to the graded portion.
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Citations
22 Claims
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1. A semiconductor device, comprising:
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a semiconductor layer; a trench disposed in the semiconductor layer; a first electrode disposed in the trench; a mesa region adjacent to the trench and being defined, at least in part, by the trench, the mesa region having a top surface and a graded region, the graded region having a doping concentration decreasing with increasing depth from the top surface of the mesa region, the doping concentration of the graded region being highest at the top surface of the mesa region, the first electrode having at least a portion electrically insulated from the mesa region; and a second electrode disposed on the top surface of the mesa region, the second electrode being a first portion of a Schottky contact, the top surface of the mesa region being a second portion of the Schottky contact. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of making a semiconductor device, comprising:
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forming a mesa region of semiconductor material in a semiconductor layer, the mesa region having a top surface; forming a graded region of the mesa region having a doping concentration decreasing with increasing depth from the top surface of the mesa region, the doping concentration of the graded region being highest at the top surface of the mesa region, the graded region having a same net conductivity type as the semiconductor layer; and forming a contact electrode on the top surface of the mesa region, the contact electrode being a first portion of a Schottky contact, the top surface of the mesa region being a second portion of the Schottky contact. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A semiconductor device, comprising:
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a semiconductor layer; a mesa region disposed in the semiconductor layer, the mesa region having a top surface and a graded region, the graded region having a doping concentration decreasing with increasing depth from the top surface of the mesa region, the doping concentration of the graded region being highest at the top surface of the mesa region, the graded region having a same net conductivity type as the semiconductor layer; a first electrode disposed in a trench within the semiconductor layer; a dielectric disposed in the trench and insulating the mesa region from the first electrode; and a second electrode having a portion disposed on the mesa region, the portion being a portion of a Schottky contact with the top surface of the mesa region. - View Dependent Claims (20, 21, 22)
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Specification