An embodiment of the invention relates to a Seebeck temperature difference sensor that may be formed in a trench on a semiconductor device. A portion of the sensor may be substantially surrounded by an electrically conductive shield. A plurality of junctions may be included to provide a higher Seebeck sensor voltage. The shield may be electrically coupled to a local potential, or left electrically floating. A portion of the shield may be formed as a doped well in the semiconductor substrate on which the semiconductor device is formed, or as a metal layer substantially covering the sensor. The shield may be formed as a first oxide layer on a sensor trench wall with a conductive shield formed on the first oxide layer, and a second oxide layer formed on the conductive shield. An absolute temperature sensor may be coupled in series with the Seebeck temperature difference sensor.