Extrinsic Photodetector Based on Co-Hyperdoped Black Silicon

Short-wavelength infrared photodetection in silicon is of interest for telecommunication and remote sensing but cannot be realized due to the limitation of silicon bandgap. Hyperdoping is an alternative method to extend detection wavebands by introducing impurity-intermediate. Here, we proposed co-hyperdoped black silicon photodiode with argon and sulfur by the use of argon ion implantation and followed pulsed laser annealing in sulfur hexafluoride. The atomic concentrations of argon and sulfur have exceeded 10 <tex-math notation="LaTeX">²⁰</tex-math> and 10 <tex-math notation="LaTeX">¹⁹</tex-math> cm <tex-math notation="LaTeX">^-3</tex-math> , respectively. The co-hyperdoped silicon has enhanced sub-bandgap absorption with an absorptance of 32.1% at 1310 nm. We prepared black silicon n <tex-math notation="LaTeX">^+</tex-math> -n photodiodes based on the larger carrier concentration gradient built in co-hyperdoped silicon layer and silicon substrate. After passivation, we obtained a room-temperature photoresponsivity of 296 mA/W and specific detectivity of 1.1 <tex-math notation="LaTeX">×</tex-math> 10 <tex-math notation="LaTeX">¹⁰</tex-math> cmHz <tex-math notation="LaTeX">1/2</tex-math> WTEXPRESERVE7 at 1310 nm.