Design and Performance of a Pinned Photodiode CMOS Image Sensor Using Reverse Substrate Bias

Abstract

A new pinned photodiode (PPD) CMOS image sensor with reverse biased p-type substrate has been developed and characterized. The sensor uses traditional PPDs with one additional deep implantation step to suppress the parasitic reverse currents, and can be fully depleted. The first prototypes have been manufactured on an 18 µm thick, 1000 Ω·cm epitaxial silicon wafers using 180 nm PPD image sensor process. Both front-side illuminated (FSI) and back-side illuminated (BSI) devices were manufactured in collaboration with Teledyne e2v. The characterization results from a number of arrays of 10 µm and 5.4 µm PPD pixels, with different shape, the size and the depth of the new implant are in good agreement with device simulations. The new pixels could be reverse-biased without parasitic leakage currents well beyond full depletion, and demonstrate nearly identical optical response to the reference non-modified pixels. The observed excessive charge sharing in some pixel variants is shown to not be a limiting factor in operation. This development promises to realize monolithic PPD CIS with large depleted thickness and correspondingly high quantum efficiency at near-infrared and soft X-ray wavelengths.

Proton and Gamma Radiation Effects on a Fully Depleted Pinned Photodiode CMOS Image Sensor

“…The sensors studied here are PPD CISs designed with full depletion capability as detailed in [12] and manufactured on a commercial 180 nm CIS process [13]. Fig.…”

“…Recently, a new PPD CIS design that can be fully depleted by applying reverse substrate bias has been demonstrated [12], [13]. This allows very thick sensitive volumes to be depleted, and has the potential to deliver the same QE as the hybrid CISs and CCDs while maintaining the advantages of monolithic PPD CISs.…”

Матричные Кмоп-Фотоприемники: Современное Состояние И Перспективы Развития

“…Другие подходы к увеличению динамического диапазона представляют собой в основном конкретные топологии пикселей для решения конкретных задач. К ним относятся логарифмические пиксели, многомодовые операции, регулировка емкости, частотная и временная работа пикселей и селективное время интеграции [2]. Верхний предел динамического диапазона определяется зарядовой емкостью пикселя, а нижний ограничивается несколькими источниками шума (тепловым, шумом считывания и др.).…”

PSF and non-uniformity in a monolithic, fully depleted, 4T CMOS image sensor

“…The sensor tested is a BSI CMOS sensor developed at The Open University [11]. It is comprised of eight sections, each with 16x32, 4T pixels, four with 10 µm pixels and four with 5.4 µm pixels.…”