Custom Silicon Technologies for High Detection Efficiency SPAD Arrays

Many applications with a potentially disruptive impact in science and technology relies on the detection of single photons in the red and in the near infrared range (e.g. 600 – 950 nm). The capability of detecting such photons with high detection efficiency, low timing jitter and high throughput is a key requirement for the successful implementation of applications ranging from single-molecule spectroscopy to quantum information processing. CMOS and BCD technologies, with small modifications to their standard process flow, allowed designers to attain remarkable results in terms of detection efficiency. However, these solutions are always forced to move in the tight boundaries set by transistors fabrication. On the contrary, technologies entirely dedicated to the fabrication of the detectors can be fully customized and allow for the free exploration of new SPAD structures. We will present our progress in developing a custom technology for the fabrication of SPAD arrays with high detection efficiency and low timing jitter. With such Red-Enhanced technology we demonstrated a peak detection efficiency of about 70% at 600 nm (40% at 800 nm) combined with a low timing jitter of less than 90 ps FWHM. This technology allows for the fabrication of SPAD arrays, but only with low fill-factor. Therefore, we will discuss also our work to make this technology suitable for high density SPAD array with even higher detection efficiency.