2020-945 Epitaxy-Enabled Substrate Transfer

SUMMARY

UCLA researchers in the Department of Materials Science and Engineering have developed a cost-effective and damage-free method to transfer a selective-area doping structure from one substrate to another via epitaxy.

BACKGROUND

Doping is ubiquitous throughout consumer electronics. Doped GaN (Gallium Nitride) is particularly useful owing to the ultra-high breakdown voltage and low on-resistance associated with these materials. Etch and regrowth and ion implantation are common methodologies used to achieve selective area doping of GaN, however, both methods suffer limitations. Etch and regrowth induces excess defectivity at the regrowth interface and ion implementation lacks doping depth while requiring for harsh conditions during the annealing process. Therefore, there is a need to introduce a damage-free and cost-effective approach to manufacture grown-in, selective-area doped active regions on free-standing GaN substrates so the full ubiquity of these materials as transistors and semiconductor LEDs can be realized.

INNOVATION

UCLA researchers in the Department of Materials Science and Engineering have developed a method to manufacture grown-in, selective-area doped active regions on free-standing GaN substrates. The method utilizes epitaxial growth (crystal growth) which imparts control over the depth of the doped layer, while achieving high uniformity in dopant concentration. Importantly, the selective-area doping profile can be realized without the need for dry etch, thus the junction interface is atomically smooth. In addition, the produced GaN substrate is suitable for vertical device structure which has greater voltage blocking capacity as well as current-handling capability. Finally, while doping of GaN is disclosed, this approach could be utilized to benefit other single crystalline materials including other families of semiconductor materials, oxides, or even metals with an improvement in production yield.

POTENTIAL APPLICATIONS