Power transistor with terminal trenches in terminal resurf regions

A device includes a transistor formed on a substrate. The transistor includes an n-type drain contact layer, an n-type drain layer, an oxide layer, a p-type body region, a p-type terminal region, body trenches, and terminal trenches. The n-type drain contact layer is near a bottom surface of the substrate. The n-type drain layer is positioned on the n-type drain contact layer. The oxide layer circumscribes a transistor region. The p-type body region is positioned within the transistor region. The p-type terminal region extends from under the oxide layer to an edge of the transistor region, thereby forming a contiguous junction with the p-type body region. The body trenches is within the transistor region and interleaves with the p-type body region, whereas the terminal trenches is outside the transistor region and interleaves with the p-type terminal region.