Low dark count rate 4H-SiC Geiger mode avalanche photodiodes operated under gated quenching at 325nm

Abstract

The detection of light at ultraviolet (UV) wavelengths is important for many military, medical and environmental applications. Applications such as biological agent detection and non-line-of-sight communications require the detection of scattered UV light. Currently, photomultiplier tubes operated as single photon counters are used to detect these low light levels, but they have many unfavorable characteristics for such applications. SiC based avalanche photodiodes (APDs) operated in Geiger mode could potentially meet the needs of these applications. Our first results, using SiC Geiger mode single photon counting avalanche photodiodes (SPADs), showed prohibitively high dark counts, due to a large tunneling current component in the multiplied dark current. Here we show the results of two p-i-n structures with 260µm and 480µm i-regions, which reduced the primary dark current by two orders of magnitude, operated under gated quenching conditions at 325nm. The lower dark current resulted in a dark count rate of 28kHz at 3.6% single photon detection efficiency (SPDE) in a 100µm diameter device. This is a three order reduction in the dark count rate over our previous results using a p-n junction SPAD.

Recent progress of SiC UV single photon counting avalanche photodiodes

“…Nowadays the highest SPDE approaching 50% has been obtained in silicon APDs with the lowest DCR of low-10 3 Hz at 530 nm [23] . A high SPDE of 37% with DCP of 2 × 10 -3 or a SPDE of 32% with DCR of 1.5 × 10 4 Hz around peak response wavelength of 280 nm has been realized in SiC APDs [20] . However, for GaN APDs, their DCP and DCR are more than one order magnitude higher than those of SiC APDs around peak response wavelength of 340 nm [12,24] .…”

“…Thus, a higher SPDE could be obtained at higher overbias, nevertheless the DCR would increase too. In order to investigate the physical mechanisms of dark current in SiC APD, temperature dependent reverse I-V characteristics can be used to de- [20,[25][26][27][28][29] , GaN [12,24] and Si APDs [23] . rive the activation energy of the dark current based on an Arrhenius plot.…”

“…Benefiting from the development of SiC material and power device technology, the first 4H-SiC single photon counting avalanche photodiode (SPAD) was reported in 2005 [18,19] . The room temperature dark count rate (DCR) of the 4H-SiC SPAD is more than one order of magnitude lower than that of GaN APD operating in Geiger mode, and its single photon detection efficiency (SPDE) is determined to be 37% at 266 nm [20] and 9.6% at 325 nm [21] . More recently, a 50-pixel linear array of 4H-SiC Geiger mode APDs was reported by Li et al with good uniformity [22] .…”

“…5. (Color online) Area normalized DCR or DCP versus SPDE for SiC[20,[25][26][27][28][29] , GaN[12,24] and Si APDs[23] .…”

High-performance 4H-SiC single photon avalanche diode operating at solar blind wavelength

“…If it is so, the "defect-free" SiC material announced on year 2004 [10] will drastically improve the performance of SiC SPADs, though such a high quality material is not commercially available yet. With today's fast development of SiC epi growth and processing technology, SiC SPADs have been reported [11] and their DCR has been significantly reduced [12].…”