This paper presents a reliable solution for power supply by using thermal energy harvesting by means of the micro thermoelectric generator (TEG). The construction of thermocouple in achieving maximum power output is investigated which include the width and length of the thermoelements for a fixed value of the thickness of thermoelements. For the structure design, several TEGs configuration is tested to foresee the temperature difference achieved between the two junctions. The materials used as substrate and thermocouple pairs are a silicon substrate and n-type/p-type polySi, respectively. The result of thermal simulations using CoventorWare shows that the etching of substrate in order to create trenches improved the efficiency of the generator significantly by providing a larger temperature difference between two junctions. Additional thermal insulator layer on top TEG surface also contributes great impact on the temperature difference achieved. A power factor of 0.0867 μW/cm-2-K2 can be obtained when the temperature difference between the bottom and the top surface of TEG is 7 K. © 2016 IEEE.