SEMICONDUCTOR DEVICE

摘要

In a semiconductor device including a bootstrap diode and a high voltage electric field transistor on a p-type semiconductor substrate, a cavity is formed in an n−-type buried layer of the semiconductor substrate to use the buried layer beneath the cavity as a drain drift region of the high voltage n-channel MOSFET, whereby a leakage current by holes that flows to the semiconductor substrate side in forward biasing of the bootstrap diode can be suppressed, and charging current for a bootstrap capacitor C1 can be increased, as well as increase in chip area can be suppressed.

主权项

1. A semiconductor device comprising:
a p-type semiconductor substrate; an n-type buried layer formed on the semiconductor substrate; an n-type semiconductor layer formed on the buried layer; a floating potential region provided in a part of the semiconductor layer; a p-type first separation region surrounding the part of the semiconductor layer where the floating potential region is provided, the first separation region being in contact with the semiconductor substrate, and spaced apart from the floating potential region to be formed in a ring-like shape; a first insulating separation region provided beneath the semiconductor layer between the floating potential region and the first separation region; a diode formed above the first insulating separation region; a p-type second separation region spaced apart from the first separation region to surround, in a ring-like shape, a region where the diode is located, and reach beneath the semiconductor layer from a surface of the semiconductor layer; an n-type source region formed in an upper part of the first separation region; and an n-type drain contact region of a transistor including the source region, the drain contact region being formed in an upper part of the semiconductor layer between a cathode region of the diode and the floating potential region.