In a general aspect, a semiconductor device can include a semiconductor region, an active region disposed in the semiconductor region, a termination region disposed on the semiconductor region and adjacent to the active region, and a resistor disposed in the termination region. The resistor can include a trench, a conductive material disposed in the trench, and a first cavity separating the trench from the semiconductor region. A portion of the first cavity can be disposed between a bottom of the trench and the semiconductor region. The resistor can further include a second cavity separating the trench from the semiconductor region.