We demonstrated a promising route for enhancing temperature sensitivity, improving saturation voltage, and reducing power consumption of the MOS(p) tunneling temperature sensors by introducing ultrathin Al2O3 into the dielectric stacks. Detailed illustrations of the working mechanism and device concept are given in this work. Three kinds of MOS(p) tunneling temperature sensors with nanoscale SiO2, HfO2, and Al2O3 dielectrics were compared comprehensively. For Al2O3 MOS(p) devices with an equivalent oxide thickness of 2 nm, the sensing performance was effectively improved and the temperature-sensitive current-voltage characteristics are reliable and reproducible. The low-temperature processing Al2O3 MOS(p) tunneling temperature sensors are potential candidates for temperature monitoring sensors on chips or biomedical systems under low thermal budget processing consideration.