單光子崩潰二極體偵測器之二次崩潰現象分析

Abstract

在本論文中，我們對TSMC 0.25 m高壓製程單光子累增崩潰二極體的二次崩潰現象進行研究。我們提出了一個新的方法評估二次崩潰效應。傳統的二次崩潰量測需要使用光子相關量測系統與短脈衝光源，而本論文僅從暗計數統計分布的量測著手。由於二次崩潰與他們的前一次崩潰有關，所以二次崩潰的統計分布會偏離Poisson分布，而我們即以此方式推算二次崩潰機率。為了驗證此方法，我們建置了一個系統量測SPAD在不同溫度下的暗計數及分析他們的統計分布。在低溫的情況下，隨著二次崩潰越來越嚴重，我們觀察到統計分布明顯的偏離了Poisson分布。除此之外，我們也以模擬找出暗計數統計分布與二次崩潰機率的量化關係。我們提出的方法不僅可適用在單一的SPAD，也能應用在整合電路的SPAD陣列中。

In this work, the afterpulsing effect in single photon avalanche diodes (SPADs) fabricated by TSMC 25HV (high voltage) CMOS process are studied. A new method for evaluating afterpulsing effect has been proposed and demonstrated. Different from conventional method requiring photon correlation measurement and short-pulsed light source, the proposed scheme is simply a measurement of dark count rate (DCR) distribution. Because the afterpulsing events correlate with their parent breakdowns, the DCR distribution deviates from the original Poisson one, which can be used to evaluate afterpulsing probability (APP). To demonstrate the validity of our method, we established a system to measure the temperature-dependent DCRs of a SPAD and analyzed their distribution. At low temperature, as the afterpulsing effect worsens, a clear non-Poisson distribution of DCRs is observed. A quantitative simulation has been performed to find out the relation between the DCR distribution and the APP. Our method is useful for evaluating APPs either in single SPADs or in circuit-integrated SPAD arrays.