Ion-implanted Al0.6Ga0.4N deep-ultraviolet avalanche photodiodes

A deep-ultraviolet Al0.6Ga0.4N p-i-n avalanche photodiode (APD) structure was grown on a (0001) AlN bulk substrate by metalorganic chemical vapor deposition. The wafer was fabricated into 20 mu m diameter mesa APD devices both with and without ion-implantation with nitrogen ions on the periphery of the p-type region of the diode mesa and tested. The dark current density vs bias, photoresponse, and the optical gain of the APDs with and without ion implantation were compared. The devices fabricated with ion implantation showed improved performance, exhibiting lower dark current densities of similar to 1 x 10(-9) A/cm(2) and a higher optical gain of similar to 5.2 x 10(5) at a current density limit of 0.3 A/cm(2). The average temperature coefficients of the reverse-bias breakdown voltage were also compared. Although the data showed negative coefficients for APDs fabricated both with and without ion implantation, the ion-implanted APDs showed an improvement relative to the devices fabricated without ion-implantation.

Automated summary

In this study, a deep-ultraviolet Al0.6Ga0.4N p-i-n avalanche photodiode (APD) was grown on an AlN bulk substrate using metalorganic chemical vapor deposition. The performance of the APDs with and without ion implantation was compared, and it was found that the devices fabricated with ion implantation showed improved performance in terms of lower dark current density and higher optical gain.