High sensitive and wide detecting range MOS tunneling temperature sensors for on-chip temperature detection

This paper examined the feasibility of applying a highly sensitive metal-oxide-semiconductor (MOS) tunneling temperature sensor, which was compatible with current CMOS technology. As the sensor was biased positively at a constant voltage, the gate current increased more than 500 times when the sensor was heated from 20 degreesC to 110 degreesC. However, when the sensor was biased at a constant-current situation, its gate voltage magnitude changed significantly with substrate temperature, with a sensitivity exceeding -2 V/degreesC. The improvement of temperature sensitivity in this paper is one thousand times over the sensitivity of a conventional p-n junction, i.e., namely, about -2 mV/degreesC. Regarding a temperature sensor array, this paper proposes a method using gate current gain, rather than absolute gate current, to eliminate the gate current discrepancy among sensors. For constant current operation, a sensitivity exceeding 10 V/degreesC can be obtained if the current level is suitable. Finally, this paper demonstrates a real temperature distribution for on-chip detection. With such a high temperature-sensitive sensor, accurate temperature detection can be incorporated into common CMOS circuits.