TY - JOUR
T1 - A Hybrid Readout Solution for GaN-Based Detectors Using CMOS Technology
AU - Padmanabhan, Preethi
AU - Hancock, Bruce
AU - Nikzad, Shouleh
AU - Bell, L. Douglas
AU - Kroep, Kees
AU - Charbon, Edoardo
PY - 2018
Y1 - 2018
N2 - Gallium nitride (GaN) and its alloys are becoming preferred materials for ultraviolet (UV) detectors due to their wide bandgap and tailorable out-of-band cutoff from 3.4 eV to 6.2 eV. GaN based avalanche photodiodes (APDs) are particularly suitable for their high photon sensitivity and quantum efficiency in the UV region and for their inherent insensitivity to visible wavelengths. Challenges exist however for practical utilization. With growing interests in such photodetectors, hybrid readout solutions are becoming prevalent with CMOS technology being adopted for its maturity, scalability, and reliability. In this paper, we describe our approach to combine GaN APDs with a CMOS readout circuit, comprising of a linear array of 1 × 8 capacitive transimpedance amplifiers (CTIAs), implemented in a 0.35 µm high voltage CMOS technology. Further, we present a simple, yet sustainable circuit technique to allow operation of APDs under high reverse biases, up to ≈80 V with verified measurement results. The readout offers a conversion gain of 0.43 µV/e−, obtaining avalanche gains up to 103. Several parameters of the CTIA are discussed followed by a perspective on possible hybridization, exploiting the advantages of a 3D-stacked technology.
AB - Gallium nitride (GaN) and its alloys are becoming preferred materials for ultraviolet (UV) detectors due to their wide bandgap and tailorable out-of-band cutoff from 3.4 eV to 6.2 eV. GaN based avalanche photodiodes (APDs) are particularly suitable for their high photon sensitivity and quantum efficiency in the UV region and for their inherent insensitivity to visible wavelengths. Challenges exist however for practical utilization. With growing interests in such photodetectors, hybrid readout solutions are becoming prevalent with CMOS technology being adopted for its maturity, scalability, and reliability. In this paper, we describe our approach to combine GaN APDs with a CMOS readout circuit, comprising of a linear array of 1 × 8 capacitive transimpedance amplifiers (CTIAs), implemented in a 0.35 µm high voltage CMOS technology. Further, we present a simple, yet sustainable circuit technique to allow operation of APDs under high reverse biases, up to ≈80 V with verified measurement results. The readout offers a conversion gain of 0.43 µV/e−, obtaining avalanche gains up to 103. Several parameters of the CTIA are discussed followed by a perspective on possible hybridization, exploiting the advantages of a 3D-stacked technology.
KW - 3D integration
KW - Avalanche photodiodes (APDs)
KW - Capacitive transimepdance amplifier (CTIA)
KW - CMOS technology
KW - Gallium nitride (GaN)
KW - Hybridization
KW - UV imaging
UR - http://resolver.tudelft.nl/uuid:7ab60f3a-0bbc-4bd5-b76f-4d5ffedbb450
UR - http://www.scopus.com/inward/record.url?scp=85041445453&partnerID=8YFLogxK
U2 - 10.3390/s18020449
DO - 10.3390/s18020449
M3 - Article
AN - SCOPUS:85041445453
SN - 1424-8220
VL - 18
SP - 1
EP - 16
JO - Sensors
JF - Sensors
IS - 2
M1 - 449
ER -