(Al, In,Ga, B)N Device Structures
Tech ID: 31880 / UC Case 2020-064-0
Uniform current-spreading is difficult to achieve in conventional LEDs due to high lateral resistance. The p-type nitride layers struggle to make p-type ohmic contacts because they demonstrate very low conductivity. While a tunnel junction can be inserted to improve contact resistance and current spreading, it requires the addition of various metals that diminish mirror reflectivity and reduce light extraction efficiency.
Researchers at the University of California, Santa Barbara have produced a nitride structure that incorporates a mirror on or above, and partially covering, a second n-type region which forms a tunnel junction via MOCVD. Leaving parts of the second n-type region uncovered allows for the formation of a metal contact to this region in subsequent metal deposition steps. Thus, different metals and metal structures can be used for the mirror region and metal contact region, allowing for precise tailoring of these regions to enhance the device’s efficiency while overcoming material obstacles.
- Increases light extraction
- Improves current spreading
- Increases device conductivity