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

In this brief, high-performance $8\times8$ 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 = $4~\mu \text{m}$ ) 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 $2\times 10^{-{14}}$ A and a high yield of 98.4%. Devices with 4- $\mu \text{m}$ 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 $10^{{4}}$ . The progress on the response performance is significant to the development of UV detection imaging.