Patent ID: 6404032
Filing Date: 2002-06-11
Classification: H01L

Abstract:
A semiconductor device comprising:a first semiconductor layer composed of a semiconductor of a first conductivity type; a second semiconductor layer of the first conductivity type having a lower impurity concentration than that of the first semiconductor layer; trench portions composed of thin trenches having a prescribed width and prescribed intervals therebetween formed in the surface of the second semiconductor layer; a semiconductor filled material composed of semiconductor of a second conductivity type, which is opposite to the first conductivity type, and filled in the trench portions; a Schottky metal electrode formed on the surface of the second semiconductor layer and the surface of the semiconductor filled material, said Schottky metal electrode forming a Schottky junction with the second semiconductor layer and an ohmic contact with the semiconductor filled material; and an ohmic metal electrode formed on the surface of the first semiconductor layer; said semiconductor device, wherein at least said second semiconductor layer and said semiconductor filled material are constituted by the same semiconductor material; when an avalanche breakdown voltage BVAK between said semiconductor filled material and said second semiconductor layer is expressed by BVAK=60Ã—(Eg/1.1)1.5Ã—(Nd/1016)âˆ’Â¾(where the unit of BVAK is V; Nd represents an impurity concentration of the second semiconductor layer and its unit is cmâˆ’3; and Eg represents an energy band gap value of the semiconductor material and its unit is eV), the width Wm between the semiconductor filled; materials adjacent to each other formed in the second semiconductor layer satisfies the following equations (1) and (2): Wm&TildeEqual;WtÃ—NdNa(1)(where the unit of the width Wm is cm; Wt represents a width of the semiconductor filled material and its unit is cm; Na represents an impurity concentration of the semiconductor filled material and its unit is cmâˆ’3) Wm&LessFullEqual;2Ã—&varepsilon;0Ã—&varepsilon;SÃ—(BVAK/n)qÃ—Nd(2)(where &egr;s represents a relative permittivity of the semiconductor material; &egr;0 represents a permittivity in vacuum and is 8.85418Ã—10âˆ’14 F/cm; q represents an elementary electrical charge and is 1.60218Ã—10âˆ’19 coulomb; and in the equation (2), n>1).