Microstructures for characterization of seebeck coefficient of doped polysilicon films

CMOS based thermoelectric micro-transducers have been demonstrated for various applications. To achieve better design and optimization of such micro-transducers, the Seebeck coefficient of doped polysilicon thin film needs to be measured accurately with respect to optimization effort in process and structure design of micro-transducers. A novel circular test structure is firstly presented to get accurate value of Seebeck coefficient in this paper, while the known planar and cantilever test structures are fabricated together and characterized separately to validate the measured Seebeck coefficient of samples with the same process conditions for comparison. Seebeck coefficient measured by the circular structure shows good agreement with the result measured by cantilever structure, while there is an error of about 14% for the result given by planar structure. The circular test structure is a good at accurate testing of the average absolute values of Seebeck coefficient of p-type and n-type. Strength and drawback for the three structures are summarized.