PRIORITY CLAIM

This application claims the priority of China application no. 202010644848.3, filed Jul. 7, 2020, which is incorporated herein by reference in its entirety.

BACKGROUND

Breakdown voltage of integrated circuits is related to the thickness of a buried oxide layer between the transistors of an integrated circuit and the substrate. Increasing the breakdown voltage for transistors of the integrated circuit increases the window of operating voltages of the integrated circuit, and extends the functional life of the integrated circuit.

