Lateral electrochemical etching of iii-nitride materials for microfabrication

Abstract

Conductivity-selective lateral etching of III-nitride materials is described. Methods and structures for making vertical cavity surface emitting lasers with distributed Bragg reflectors via electrochemical etching are described. Layer-selective, lateral electrochemical etching of multi-layer stacks is employed to form semiconductor/air DBR structures adjacent active multiple quantum well regions of the lasers. The electrochemical etching techniques are suitable for high-volume production of lasers and other III-nitride devices, such as lasers, HEMT transistors, power transistors, MEMs structures, and LEDs.

What is claimed is: 
     
         1 . A III-nitride DBR device comprising:
 a multi-layer structure having first and second layers formed of III-nitride material, wherein a conductivity of the first layers is different from a conductivity of the second layers;   a MQW structure formed adjacent the multi-layer structure, wherein the MQW structure comprises an active region of the device;   vias formed into the multi-layer structure proximal to the MQW structure; and   regions adjacent the vias in which portions of the second layers have been completely removed to form at least two first layers separated by one or more layers of air.   
     
     
         2 . The DBR device of  claim 1 , wherein the MQW structure forms an active region of a laser. 
     
     
         3 . The DBR device of  claim 1 , wherein the first layers and second layers comprise GaN. 
     
     
         4 . The DBR device of  claim 3 , wherein the second layers comprise high n-type conductivity material. 
     
     
         5 . The DBR device of  claim 1 , wherein the thicknesses of the first layers are substantially the same. 
     
     
         6 . The DBR device of  claim 1 , wherein the thicknesses of the first layers correspond to approximately one-quarter of a selected emission wavelength for the laser. 
     
     
         7 . The DBR device of  claim 1 , wherein the removed portions of the second layers and remaining first layers form a structure having periodic contrast of optical refractive index.