Semiconductor device and manufacturing method thereof

摘要

In a semiconductor device, a logic MOSFET and a switch MOSFET are formed in a high-resistance substrate. The logic MOSFET includes an epitaxial layer formed on the high-resistance substrate and a well layer formed on the epitaxial layer. The switch MOSFET includes a LOCOS oxide film formed on the high-resistance substrate, the LOCOS oxide film being sandwiched between trenches and thus having a mesa-shape in its upper part. The switch MOSFET further includes a buried oxide film and a SOI layer formed on the mesa-shape of the LOCOS oxide film. The upper surface of the mesa-shape of the LOCOS oxide film is positioned at the same height as the upper surface of the epitaxial layer.

主权项

1. A semiconductor device comprising:
a first MOSFET formed on a high-resistance substrate; and a second MOSFET that is monolithic-integrated with the first MOSFET on the high-resistance substrate, wherein the first MOSFET comprises:
a first semiconductor layer formed on the high-resistance substrate; anda second semiconductor layer formed above the first semiconductor layer, the second semiconductor layer serving as a well layer of the first MOSFET, and the second MOSFET comprises:
a first insulating layer formed on the high-resistance substrate, first insulating layer being sandwiched between two trenches and thus having a mesa-shape in its upper part, an upper surface of the mesa-shape being positioned at the same height as the first semiconductor layer;a second insulating layer formed on the mesa-shape of the first insulating layer; anda third semiconductor layer formed on the second insulating layer, the third semiconductor layer serving as a well layer of the second MOSFET.