Patent ID: 8716141
Filing Date: 2014-05-06
Classification: H01L

Abstract:
1. A method of forming a III-N device, comprising: forming an electrode-defining layer having a thickness on a surface of a III-N material structure that has a 2DEG formed therein; patterning a masking layer over the electrode-defining layer, the masking layer including an opening having a width; performing an etching step, the etching step comprising etching the electrode-defining layer beneath the opening to form a recess therein, the recess having a sidewall which comprises a plurality of steps, a portion of the recess distal from the III-N material structure having a first width, and a portion of the recess proximal to the III-N material structure having a second width, the first width being larger than the second width; removing the masking layer; and forming an electrode in the recess, the electrode including an extending portion over the sidewall, a portion of the electrode-defining layer being between the extending portion and the III-N material structure; wherein the etching step includes a first procedure and a second procedure, the first procedure comprising removing a portion of the electrode-defining layer, and the second procedure comprising removing a portion of the masking layer without entirely removing the masking layer and without substantially etching the electrode-defining layer, the second procedure causing an increase in the width of the opening in the masking layer, wherein the masking layer comprises photoresist; wherein the method further comprises redistributing the photoresist in the masking layer prior to performing the etching step; and wherein redistributing the photoresist causes the masking layer to have slanted sidewalls adjacent to the opening.