Field-effect transistor and manufacturing method thereof

Abstract

Disclosed are a field-effect transistor and a manufacturing method thereof. The disclosed field-effect transistor includes: a semiconductor substrate; a source ohmic metal layer formed on one side of the semiconductor substrate; a drain ohmic metal layer formed on another side of the semiconductor substrate; a gate electrode formed between the source ohmic metal layer and the drain ohmic metal layer, on an upper portion of the semiconductor substrate; an insulating film formed on the semiconductor substrate's upper portion including the source ohmic metal layer, the drain ohmic metal layer and the gate electrode; and a plurality of field electrodes formed on an upper portion of the insulating film, wherein the insulating film below the respective field electrodes has different thicknesses.

What is claimed is: 
     
         1 . A field-effect transistor comprising:
 a semiconductor substrate;   a source ohmic metal layer formed on one side of the semiconductor substrate;   a drain ohmic metal layer formed on another side of the semiconductor substrate;   a gate electrode formed between the source ohmic metal layer and the drain ohmic metal layer on an upper portion of the semiconductor substrate;   an insulating film formed on the semiconductor substrate's upper portion comprising the source ohmic metal layer, the drain ohmic metal layer and the gate electrode; and   a plurality of field electrodes formed on an upper portion of the insulating film,   wherein the insulating film below the respective field electrodes has different thicknesses.   
     
     
         2 . The field-effect transistor as claimed in  claim 1 , wherein the insulating film comprises at least one selected from the group including silicon nitride, silicon oxide, HfO 2 , BCB and a porous silica thin film. 
     
     
         3 . The field-effect transistor as claimed in  claim 1 , wherein a kind and a thickness of the insulating film are determined in consideration of an etch rate of the insulating film and etch rates of respective photosensitive films, except for an uppermost photosensitive film from among the multi-layered photosensitive films used in an insulating film etching process.