Nitride semiconductor substrate, semiconductor device, and methods for manufacturing nitride semiconductor substrate and semiconductor device

Abstract

A nitride semiconductor substrate having a main surface serving as a semipolar plane and provided with a chamfered portion capable of effectively preventing cracking and chipping, a semiconductor device fabricated using the nitride semiconductor substrate, and a method for manufacturing the nitride semiconductor substrate and the semiconductor device are provided. The nitride semiconductor substrate includes a main surface inclined at an angle of 71° or more and 79° or less with respect to the (0001) plane toward the [1-100] direction or inclined at an angle of 71° or more and 79° or less with respect to the (000-1) plane toward the [−1100] direction; and a chamfered portion located at an edge of an outer periphery of the main surface. The chamfered portion is inclined at an angle θ 1 or θ 2 of 5° or more and 45° or less with respect to adjacent one of the main surface and a backside surface on a side opposite to the main surface. Accordingly, cracking and chipping occurring from the edge of the outer periphery of the nitride semiconductor substrate can be effectively suppressed.

1 - 5 . (canceled) 
     
     
         6 : A method for manufacturing a nitride semiconductor substrate, comprising the steps of:
 preparing a nitride semiconductor substrate having a main surface inclined at an angle of 71° or more and 79° or less with respect to a (0001) plane toward a [1-100] direction or inclined at an angle of 71° or more and 79° or less with respect to a (000-1) plane toward a [−1100] direction; and   chamfering an edge of an outer periphery of said main surface of said nitride semiconductor substrate,   said step of chamfering the edge includes the step of forming a chamfered portion inclined at an angle of 5° or more and 45° or less with respect to adjacent one of said main surface and a backside surface on a side opposite to said main surface.   
     
     
         7 : A method for manufacturing a semiconductor device, comprising the steps of:
 preparing a nitride semiconductor substrate using the method for manufacturing a nitride semiconductor substrate according to  claim 6 ; and   forming an epitaxial layer on said main surface of said nitride semiconductor substrate.