Semiconductor Device and Method for Manufacturing a Semiconductor Device

Abstract

A semiconductor device includes a semiconductor material having a bandgap larger than 2 eV and less than 10 eV, and a contact layer in contact with the semiconductor material. The contact layer includes a metal nitride. A non-ohmic contact is formed between the semiconductor material and the contact layer.

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a semiconductor material having a bandgap larger than 2 eV and less than 10 eV;   a contact layer in contact with the semiconductor material, the contact layer comprising a metal nitride, wherein a nitrogen content of the metal nitride is 10 to 45 at-%; and   a non-ohmic contact formed between the semiconductor material and the contact layer.   
     
     
         2 . The semiconductor device of  claim 1 , wherein the semiconductor material comprises SiC. 
     
     
         3 . The semiconductor device of  claim 1 , wherein the metal nitride comprises a combination of a stoichiometric compound with a non-stoichiometric compound including the metal and nitrogen. 
     
     
         4 . The semiconductor device of  claim 1 , wherein the metal nitride comprises a metal selected from the group consisting of molybdenum, titanium, tantalum, and tungsten. The semiconductor device of  claim 1 , wherein the non-ohmic contact is a Schottky contact. 
     
     
         6 . The semiconductor device of  claim 1 , wherein the non-ohmic contact is a rectifying contact. 
     
     
         7 . An electrical component comprising the semiconductor device of  claim 1 , wherein the electrical component is selected from the group consisting of a Schottky diode, a merged pn Schottky diode, a JFET, a MESFET, an integrated flyback diode, a rectifier, an inverter, and a power supply. 
     
     
         8 . A semiconductor device, comprising:
 a semiconductor body comprising a semiconductor material having a bandgap larger than 2 eV and less than 10 eV;   a contact layer in contact with a first surface of the semiconductor body, the contact layer comprising a metal nitride, wherein a nitrogen content of the metal nitride is 10 to 45 at-%, the contact layer being electrically connected to a first load terminal; and   a non-ohmic contact formed between the semiconductor body and the contact layer,   wherein a second surface of the semiconductor body is electrically connected to a second load terminal, the second surface being opposite to the first surface.   
     
     
         9 . The semiconductor device of  claim 8 , further comprising a doped portion in contact with the contact layer, the doped portion being embedded in the semiconductor body and having a conductivity type opposite to the conductivity type of the semiconductor body. 
     
     
         10 . A method of manufacturing a semiconductor device, the method comprising:
 forming a contact layer in contact with a semiconductor material, so as to form a non-ohmic contact between the semiconductor material and the contact layer, the semiconductor material having a bandgap larger than 2 eV and less than 10 eV, the contact layer comprising a metal nitride,   wherein forming the contact layer comprises selecting a composition ratio of the metal nitride, thereby setting a work function of the contact layer.   
     
     
         11 . The method of  claim 10 , wherein the semiconductor material comprises SiC. 
     
     
         12 . The method of  claim 10 , wherein the contact layer is formed by a reactive sputtering process using nitrogen as a reactant. 
     
     
         13 . The method of  claim 12 , wherein a partial pressure of nitrogen during the reactive sputtering process is set so as to form the metal nitride comprising a mixed phase of MN and M 2 N, wherein M denotes the metal. 
     
     
         14 . The method of  claim 13 , wherein a ratio of the nitrogen partial pressure and the total pressure during the sputtering process is in a range of 0.1 to 1.0. 
     
     
         15 . The method of  claim 13 , wherein. the partial pressure of nitrogen during the reactive sputtering process is set so as to set the work function of the contact layer. 
     
     
         16 . The method of  claim 10 , wherein the metal nitride comprises a metal selected from the group consisting of molybdenum, titanium, tantalum, and tungsten.