High temperature storage for energy harvesting in hostile environments

This work presents the first demonstration of high temperature energy storage, using HfO₂ MIM capacitors, for energy scavenging in hostile environments. The work builds upon previous efforts to make capacitors operational at temperatures in excess of 600 K and aims to provide a scalable capacitor based storage technology. Presented are the results of storage decay for both 35 nm and 60 nm HfO₂ dielectrics with device areas between 0.785 × 10^-4 cm² and 1.02 × 10^-3 cm². Results show a 10 fold reduction in open circuit voltage decay (OCVD) rate for the thicker dielectric devices. It was also shown that the OCVD rate can be decreased with serial connection of the capacitors, further increasing the stability of the stored voltage with temperature. The effect of reducing the capacitance by increasing the dielectric thickness does not have a detrimental effect on the OCVD rate due to the substantial reduction in dielectric leakage.