Progress and challenges in GaN-on-Si LEDs

William Fenwick

doi:10.1117/12.2209679

8 March 2016 Progress and challenges in GaN-on-Si LEDs

William Fenwick

Proceedings Volume 9768, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XX; 97680W (2016) https://doi.org/10.1117/12.2209679
Event: SPIE OPTO, 2016, San Francisco, California, United States

Abstract

Silicon substrates offer a variety of advantages over conventional LED substrates, including both their low cost and their compatibility with the existing semiconductor manufacturing infrastructure. Researchers have sought to avail themselves of these benefits by developing GaN LEDs on silicon substrates. Integration of the two materials, however, presents several technical challenges that have proven difficult to address. The main challenges are the large lattice mismatch between GaN and silicon and the large difference in thermal expansion coefficients. Solutions have begun to emerge in recent years, with Toshiba being the first to commercialize GaN-on-Si technology on 200mm substrates in 2013, and several companies now shipping GaN-on-Si LEDs. Toshiba has developed a novel buffer layer structure and MOCVD growth technology that controls strain, wafer bow, and cracking while also suppressing formation of dislocations. This technology allows for the growth of GaN epitaxial layers with minimal cracking and dislocation densities in the low 10⁸ cm^-2. Control of strain and wafer bow is critical for the epitaxial process, and this requires very fine control over both absolute wafer temperature and temperature uniformity. Toshiba’s technology controls temperature uniformity very well, and Toshiba has demonstrated wavelength uniformity with σ=2nm across a 200mm wafer. Thin film LEDs fabricated from these materials have efficiencies on par with the best efficiencies of LEDs grown on conventional substrates. Blue LED wall-plug efficiencies of ~83% are demonstrated.

Citation Download Citation

William Fenwick "Progress and challenges in GaN-on-Si LEDs", Proc. SPIE 9768, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XX, 97680W (8 March 2016); https://doi.org/10.1117/12.2209679

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available