Edge-Emitting Laser Diode with Via-Activated Tunnel Junction Contact
Tech ID: 31863 / UC Case 2019-966-0
P-GaN demonstrates poor bulk conductivity and high specific contact resistivity as a result of its thickness. In principle, reducing thickness significantly reduces the operating voltage of p-GaN, but in doing so there will be an increase in the modal loss of the laser and a requirement for a metal or TCO-to-p-GaN contact will be introduced.
Researchers at the University of California, Santa Barbara have created a novel InGaN quantum well edge-emitting laser diode with a via-activated tunnel junction p-contact that achieves higher conductivity without increased modal loss or an additional TCO contact. The device uses an MOCVD-grown tunnel junction contact for the p-side, consisting of a p++ GaN layer, an n- GaN layer and an n+ GaN contact layer. Vias are formed in the top n-type GaN layers through dry etching or by using a SiO2 mask and selective area regrowth. The p and p++ GaN layers are activated through these layers by thermal anneal. This affords the reduced p-GaN thickness (below 250 nm) and eliminates the need for a metal or TCO-to-p-GaN contact. The device can be grown completely by MOCVD.
- Increases conductivity
- Reduces p-GaN thickness
- Eliminates need for metal TCO-to-p-GaN contact
- Highly implementable with MOCVD