Uncooled Infrared Detection Using CMOS Transistor-Based Sensors

In this article, we investigate the sensing capabilities of
$8\times8$
complementary metal–oxide–semiconductor (CMOS) micromachined structures with thermal sensing transistors operating in both the subthreshold and saturation region for uncooled infrared detection. Unlike conventional microbolometer materials that require additional deposition steps, we leverage transistors integrated within a CMOS process to achieve comparable sensitivity in response to infrared-induced temperature changes. The enhanced sensitivity is attributed to the variation in carrier mobility and threshold voltage of the transistors. The sensors are fabricated in a 0.35-
$\mu \text{m}$
CMOS process, each occupying an area of
$46\times36\,\,\mu \text{m}^{{2}}$
. In our experiments, the operation in the subthreshold region exhibited a responsivity of
$12\times106$
V/W and a noise equivalent temperature difference (NETD) of 563 mK at atmospheric pressure. In contrast, the saturation region presented an improved responsivity of
$17.2\times106$
V/W and a lower NETD of 390 mK at atmospheric pressure. The results demonstrate the great potential of CMOS transistors as promising devices for uncooled infrared detection.