[Zurück]

M. Hofbauer:
"Precise Distance Measurement with Thick SPADs";
Vortrag: The International SPAD Sensor Workshop (ISSW 2022), Graz (eingeladen); 13.06.2022 - 15.06.2022.

The performance of thick SPADs especially with respect to precision distance measurements is presented. These SPADs are integrated in 0.35 µm CMOS; comprising an approximately 12 µm thick epitaxial layer, which inreases the photon detection efficency, especially for longer wavelengths that penetrate deeper into silicon. With an excess bias of 6.6 V, photon detection probabilities of 37%, 35%, and 28% are reached for wavelengths of 780 nm, 800 nm, and 850 nm, respectively. Using SPADs enables sensitive and precise time-of-flight (TOF) measurements. A distance precision slightly below 1 mm is achieved with an integrated indirect TOF (iTOF) sensor with integrates thick SPAD. The sensitivity of the sensor is improved by 3-4 orders of magnitude compared to a PIN iTOF sensor in the same technology. Using interferometric approaches, the distance precision can be further improved down to the µm range. The phase correlating sensor for iTOF is fully compatible with a frequency modulated continuous wave (FMCW) laser. Our FMCW setup allows using relatively low-cost lasers without strong limitations regarding linearity.