Indirect-coupling ultraviolet-sensitive photodetector with high electrical gain, fast response, and low noise

• Published in: Sensors and actuators. A. Physical. 2000-10, Vol.86 (1), p.66-72
• Main Authors: Qian, F, Schnupp, R, Chen, C.Q, Helbig, R, Ryssel, H
• Format: Article
• Language: English
• Subjects: Applied sciences; Conductors, resistors (including thermistors, varistors, and photoresistors); Electrical gain; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Imaging detectors and sensors; Indirect coupling; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Low noise; Optical elements, devices, and systems; Optical instruments, equipment and techniques; Optics; Physics; Response time; UV photodetector
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(00)00444-1

In this paper, design, properties, and fabrication of a novel indirect-coupling UV-sensitive photodetector (ICUP) are presented. It consists of a shallow p–n photoelectric conversion junction and an n–p–n output transistor. The ICUP features some advantages compared to phototransistors and photodiodes: a broader response spectrum, a lower noise, a higher responsivity and a shorter response time. The high responsivity in the UV region is achieved by a shallow p–n junction that works as active photoelectric conversion region. The dark current is two orders of magnitude smaller than that of the phototransistor fabricated using the same process. The ICUP also features an electrical gain of about 20. Under a bias voltage of 20 V, its response time reaches 750 ns, which is about three times shorter than that of the phototransistor.