The disclosed embodiments relate to the design of a temperature sensor, which is integrated into a semiconductor chip. This temperature sensor comprises an electro-thermal filter (ETF) integrated onto the semiconductor chip, wherein the ETF comprises: a heater; a thermopile, and a heat-transmission medium that couples the heater to the thermopile, wherein the heat-transmission medium comprises a polysilicon layer sandwiched between silicon dioxide layers. It also comprises a measurement circuit that measures a transfer function through the ETF to determine a temperature reading for the temperature sensor.