This letter presents a novel ultraviolet photon counting system based on a SiC SPAD array. The detector is made of 4H-SiC with a fairly low dark current in pA level and the array size is $1\times 128$ . In order to reduce the influence of dark count on image quality, this letter proposes an adaptive sampling readout circuit system, which can automatically adjust the SPAD hold-off time according to the photon density of the applications. Aiming at the nonuniform breakdown voltage of SPADs in a linear array, an adjustable bias voltage circuit is adopted to realize the accurate adjustment of pixel SPAD’s bias voltage. The ROIC is taped out in TSMC 0.18 $\mu {\mathrm{ m}}$ standard CMOS process and connected to the SPAD array by a gold bonding package. Based on the self-developed imaging system, UV photon counting imaging and deep violet- visible light fusion imaging are realized for the first time.

中文翻译：

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基于碳化硅SPAD阵列的紫外光子计数成像系统

这封信提出了一种基于 SiC SPAD 阵列的新型紫外光子计数系统。探测器由 4H-SiC 制成，具有相当低的 pA 级暗电流，阵列尺寸为 $1\乘以 128$ . 为了减少暗计数对图像质量的影响，本文提出了一种自适应采样读出电路系统，可以根据应用的光子密度自动调整SPAD释抑时间。针对线性阵列中SPAD击穿电压不均匀的问题，采用可调偏置电压电路实现像素SPAD偏置电压的精确调节。ROIC 在 TSMC 0.18 中流片 $\mu {\mathrm{ m}}$ 标准 CMOS 工艺，并通过金键合封装连接到 SPAD 阵列。基于自主研发的成像系统，首次实现了紫外光子计数成像和深紫-可见光融合成像。