Diode

• US 20070194364A1
• Filed: 04/20/2007
• Published: 08/23/2007
• Est. Priority Date: 08/30/2001
• Status: Active Grant

• Current Assignee: Shindengen Electric Manufacturing Company Limited
• Original Assignee: Shindengen Electric Manufacturing Company Limited
• Inventors: Sugai, Akihiko, Kunori, Shinji, Oshima, Kosuke, Kitada, Mizue, Kurosaki, Toru
• Granted Patent: US 7,855,413 B2
• Time in Patent Office: Days
• US Class Current: 257/302
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• CPC Class Codes: H01L 29/0634 Multiple reduced surface field (multi-RESURF) structures, e.g. double RESURF, charge compensation, cool, superjunction (SJ), 3D-RESURF, composite buffer (CB) structures
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/66348 with a recessed gate
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A transistor and diode having a low resistance and a high breakdown voltage are provided. When the bottom portion of a narrow trench having the shape of a rectangular parallelepiped is filled with a semiconductor grown by epitaxial method, a {1 0 0} plane is exposed at the sidewalls of the narrow trench. The semiconductor is epitaxially grown at a constant rate on each sidewall of the narrow trench; thereby, creating a filling material with no voids present therein. The concentration and width of the filling material are optimized. This allows the portion located between the filling materials in a drain layer to be completely depleted when the filling material is completely depleted; thereby, making it possible to establish an electric field having a constant strength in the depletion layer extended in the drain layer.

Claims

1. -8. (canceled)

9. A diode comprising:

a semiconductor substrate having single crystal structure of first conductivity type;

a principal semiconductor layer of a first conductivity type grown on the surface of said semiconductor substrate, and the principal semiconductor layer having a {1100 plane surface, said surface being defined by an x-axis and an orthogonal y-axis, the x and y axes coinciding with crystallographic axes of the single crystal;

a narrow trench formed in the principal semiconductor layer and the 100} plane surface of a crystal structure of the principal semiconductor layer being exposed on a bottom and sidewalls of the narrow trench;

a filling material having a oriented surface same as that of the principal semiconductor layer and being formed of an epitaxially grown semiconductor in the narrow trench and doped with a dopant of a second conductivity type; and

a Schottky electrode in contact with both surfaces of the principal semiconductor layer and the filling material, the Schottky electrode forming a Schottky junction with the principal semiconductor layer and forming an ohmic contact to the filling material;

an ohmic electrode formed on the back surface of the semiconductor substrate and forming ohmic contact to the semiconductor substrate.

10. The diode according to claim 9, wherein the Schottky junction and P-N junction between the filling material and the principal semiconductor layer are forward biased or reverse biased together by applying voltage between the Schottky electrode and the ohmic electrode.

11. The diode according to claim 10, wherein a width and an impurity concentration of the filling material, and interval between the filling materials and an impurity concentration of the principal semiconductor layer are made values so as to contact depletion layers extended from the P-N junction each other when the filling material is depleted.