Enhanced seebeck coefficient for a compressive n-type polysilicon film

•Enhanced Seebeck coefficient for a compressive n-type polysilicon film is proposed.•A higher S of 260 μV/K for a polysilicon film fabricated on a gate oxide is found.•Mechanical strain can improve the thermoelectric performance of a polysilicon film.

An enhanced Seebeck coefficient (S) for a compressive n-type polysilicon film is proposed. An approximate value for S of 260 μV/K for a polysilicon film fabricated on a gate oxide (polyGOI) is greater than the value of 210 μV/K for a polysilicon film fabricated on a field oxide (polyFOX). The cause for this difference in the value of S is attributed to the two ends of the upward polyGOI edge caused by the local oxidation of silicon process that induces a compressive stress in the polysilicon film relative to the polyFOX. A four-point bending experiment also provides strong evidence for the enhancement in S.