DC/DC converter circuit of semiconductor device having a first transistor of a normally-off type and a second transistor of a normally-on type

摘要

A semiconductor device including a DC/DC converter circuit, in which the DC/DC converter circuit includes a transistor of a normally-off type, having a first drain electrode connected to an input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer, and a transistor having a second drain electrode connected to the first source electrode and a grounded second source electrode.

主权项

1. A semiconductor device comprising:
a DC/DC converter circuit, wherein the DC/DC converter circuit includes a first transistor of a normally-off type, having a first drain electrode connected to an input terminal and a first source electrode connected to an output terminal, which is formed in a first compound semiconductor substrate having a two-dimensional electron gas layer; a second transistor of a normally-on type, having a second drain electrode connected to the first source electrode and a grounded second source electrode, which is formed in the first compound semiconductor substrate; a drain pad disposed opposite to the second transistor across the first transistor, the first drain electrode of the first transistor being connected to the drain pad; a source pad disposed opposite to the first transistor across the second transistor, the grounded second source electrode of the second transistor being connected to the source pad; and a first pad disposed between the first transistor and the second transistor, the first source electrode of the first transistor and the second drain electrode of the second transistor being connected to the first pad, wherein a recess is formed in a surface of the first compound semiconductor substrate, wherein the first transistor has a first gate electrode of which at least a portion is located within the recess, and wherein the second transistor has a second gate electrode of which a lower end is located above a surface of the first compound semiconductor substrate.