Uncooled CMOS Integrated Triple-Band Terahertz Thermal Detector Comprising of Metamaterial Absorber and PTAT Sensor

This paper presents an uncooled monolithic resonant triple-band terahertz (THz) thermal detector using a 55 nm complementary metal oxide semiconductor (CMOS) process. The novel integration of a compact triple-band metamaterial (MM) absorber coupled with a sensitive proportional to absolute temperature (PTAT) sensor leads to a compact, uncooled, cost-effective, easy-integration, and mass-production CMOS integrated triple-band THz thermal detector. The principles of operation and physical modeling such as selective absorption of electromagnetic energy, thermal energy conversion, and electrical response are demonstrated. The triple-band MM absorber achieves high absorption magnitudes of 90.4%, 96.8%, and 98.8% at 0.91, 2.58, and 4.3 THz respectively. The optimized PTAT sensor shows a high temperature coefficient of voltage of 10.11 mV/°C. Simulated responsivities are 37.28 V/W at 0.91 THz, 49.9 V/W at 2.58 THz, and 61.11 V/W at 4.3 THz. The proposed triple-band THz thermal detector shows calculated noise equivalence powers (NEPs) of 1.07, 1.6, and
$1.31~\mu \text{W}$
/Hz
^0.5
at 0.91, 2.58, and 4.3 THz respectively. Relatively better experimental results are obtained at 0.91 THz and 2.58 THz due to the scarcity of THz sources. The proposed detector achieves maximum responsivities of 33.4 V/W and 47.9 V/W, while minimum NEPs of
$1.49~\mu \text{W}$
/Hz
^0.5
at 0.91 THz with a modulation frequency of 2 Hz, and
$1.88~\mu \text{W}$
/Hz
^0.5
at 2.58 THz with a modulation frequency of 0.5 Hz.