Design, fabrication, and characterization of a high-performance CMOS-compatible thermopile infrared detector with self-test function

Abstract

This paper presents the design, fabrication and characterization of a CMOS-compatible thermopile infrared (IR) detector with self-test function based on XeF2 front-side dry etching. In order to achieve better performance, a heavily doped N/P-polysilicon is utilized to form thermocouples, and front-side isotropic etching is adopted to release and thermal isolation. At the same time, a platinum heater on the absorption layer is designed to serve as a heat source to realize the self-test function of the thermopile IR detector. IR radiation sensing shows that the detector achieves relatively high responsivity of 160.03 V W−1 and detectivity of and a extremely short response time of 2.5 ms in air at room temperature. In addition, a self-test measurement is conducted and validated by applying a voltage to the heater. Compared with traditional methods for detecting thermopile performance, this method has obvious convenience and simplicity, which provides an effective way for performance monitoring of thermal-based devices.

A Highly Accurate Method for Measuring Response Time of MEMS Thermopiles

“…As Al is compatible with the CMOS process and easier to be patterned in the manufacturing process, therefore, Al is adopted as the material of microheater in this work. To further verify the conception, the properties of Pt and PolySi are compared and analyzed with those of Al in the following work, since previous studies mostly used Pt and PolySi as the microheater materials [ 5 , 27 , 30 , 31 ].…”

“…Traditionally, the test of response time requires a complex system involving a blackbody radiation source, a chopper, and other equipment. With rotation of the chopper blades, the test system provides a changing radiation so that the sensor outputs the corresponding voltage, from which the response time of the device can be obtained [ 20 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Nevertheless, it takes time for the chopper blades to rotate, which prolongs the response time of the device.…”

A Thermopile Infrared Sensor Array Pixel Monolithically Integrated with an NMOS Switch

“…As a side note, MEMS thermopiles sensors are used as important uncooled bolometers and pyroelectric detectors [26,27] and this type of sensor with high performance can be mass-produced by using standard CMOS processes [28][29][30][31]. This makes it possible for MEMS thermopiles and CMOS ICs to be integrated on the same chip by adopting interleaved MEMS and CMOS processing.…”

The Study of Reactive Ion Etching of Heavily Doped Polysilicon Based on HBr/O2/He Plasmas for Thermopile Devices

“…Polysilicon, including both undoped and heavily doped polysilicon, has many important applications in complementary metal oxide semiconductor (CMOS) and micro electro mechanical systems (MEMS) technologies [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Compared to undoped polysilicon, heavily doped polysilicon has higher Seebeck coefficient, lower electrical resistivity and thermal conductivity.…”