Integrable quasi-vertical gallium nitride power UMOSFETs and their application to monolithic optoelectronic integration

Abstract

The GaN UMOSFET/LED optoelectronic integrated pairs are demonstrated using selective epi removal approach. The fabrication processes combine integrable LEDs with integrable quasi-vertical UMOSFETs. Functional GaN quasi-vertical power UMOSFET/LED pairs are the first demonstration in the world. The controllable modulation of LED current and light output power (LOP) with varying VDD and VGS of the integrated UMOSFET is verified. At VGS = 36 V and VDD = 20 V, LOP of 4.9 W/cm2 (or 6.0 mW) is obtained on an integrated device with a 350μm×350μm LED. The trade-off between FET area coverage and FET power dissipation is studied; a tested device with the best trade-off has FET/LED area ratio of 24% and FET/LED power ratio of 56%. The integrated device with a 3-LED chain driven by one FET is functional and exhibits an optical bandwidth of 9 MHz in the high-frequency modulation test. In addition, the integrated LED turns on at 5 V, with peak EQE of 2.4% and peak wavelength of 484 nm.