Patent ID: 7319076

Claim:
A method, comprising: defining a void in a sacrificial layer proximate to an active layer with a first etching substance reactive with the sacrificial layer, wherein the first etching substance comprises a mixture of H 2 SO 4 , H 2 O 2 , and H 2 O; forming an overgrowth layer in the void and over portions of the sacrificial layer adjacent to the void, wherein the overgrowth layer comprises one of InP or AlGaAs; defining a ridge section in the overgrowth layer with a second etching substance reactive with the overgrowth layer and substantially non-reactive with the sacrificial layer, wherein the second etching substance comprises a mixture of hydrochloric acid (HCl) and phosphoric acid (H 3 PO 4 ; and removing portions of the sacrificial layer to define a shank section in the overgrowth layer under the ridge section, the ridge section having a greater lateral dimension than the shank section to reduce electrical resistance between the active layer and electrical interconnects to be electrically coupled to the ridge section.