High-Speed and Responsivity 4H-SiC 8 × 8 p-i-n Ultraviolet Photodiode Arrays With Micro-Hole Structure

In this brief, high-performance <inline-formula> <tex-math notation="LaTeX">$8\times8$ </tex-math></inline-formula> arrays of 4H-SiC p-i-n ultraviolet (UV) photodiodes (PDs) with micro-hole structure are demonstrated. In order to improve the performance of the device, a periodic micro-hole structure (diameter = <inline-formula> <tex-math notation="LaTeX">$4~\mu \text{m}$ </tex-math></inline-formula>) was etched from the cap layer (p⁺ layer) to the i layer, which will elevate the effective absorption of UV light. The pixels in 4H-SiC p-i-n array show a low dark current of less than <inline-formula> <tex-math notation="LaTeX">$2\times 10^{-{14}}$ </tex-math></inline-formula> A and a high yield of 98.4%. Devices with 4-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> micro-hole reach a peak spectral responsivity of 0.159 A/W at 280 nm, which is 23.3% higher than that of the device without micro-hole. Moreover, the device has a faster response time of 2.2 ns and a high UV/visible rejection ratio of more than <inline-formula> <tex-math notation="LaTeX">$10^{{4}}$ </tex-math></inline-formula>. The progress on the response performance is significant to the development of UV detection imaging.