Semiconductor device comprising bipolar and unipolar transistors including a concave and convex portion

摘要

A combined switching device includes a MOSFET disposed in a MOSFET area and IGBTs disposed in IGBT areas of a SiC substrate. The MOSFET and the IGBTs have gate electrodes respectively connected, a source electrode and emitter electrodes respectively connected, and a drain electrode and a collector electrode respectively connected. The MOSFET and the IGBTs are disposed with a common n-buffer layer. A top surface element structure of the MOSFET and top surface element structures of the IGBTs are disposed on the first principal surface side of the SiC substrate. Concave portions and convex portions are disposed on the second principal surface side of the SiC substrate. The MOSFET is disposed at a position corresponding to the convex portion of the SiC substrate. The IGBTs are disposed at positions corresponding to the concave portions of the SiC substrate.

主权项

1. A semiconductor device having at least one or more bipolar transistors and at least one or more unipolar transistors disposed on a semiconductor substrate of a first conductivity type and made of a semiconductor material with a band gap larger than silicon, the semiconductor device comprising:
a first semiconductor layer of the first conductivity type and constituting the semiconductor substrate on a first principal surface side of the semiconductor substrate; a second semiconductor layer of the first conductivity type and constituting the semiconductor substrate on a second principal surface side of the semiconductor substrate, the second semiconductor layer having an impurity concentration higher than the first semiconductor layer; a third semiconductor layer of the first conductivity type disposed between the first semiconductor layer and the second semiconductor layer to be in contact with at least the first semiconductor layer; a concave portion disposed on the second principal surface side of the semiconductor substrate and penetrating the second semiconductor layer to the third semiconductor layer; a fourth semiconductor layer of a second conductivity type and disposed on a bottom surface of the concave portion to be in contact with the third semiconductor layer; an output electrode of the bipolar transistor, contacting the fourth semiconductor layer; an input electrode and a control electrode of the bipolar transistor disposed on the first principal surface side of the semiconductor substrate at a position corresponding to the concave portion; a convex portion formed on the second principal surface side of the semiconductor substrate, correspondingly to the concave portion; an output electrode of the unipolar transistor disposed on a surface of the convex portion to be electrically connected to the output electrode of the bipolar transistor; an input electrode of the unipolar transistor disposed on the first principal surface side of the semiconductor device at a position corresponding to the convex portion to be electrically connected to the input electrode of the bipolar transistor; and a control electrode of the unipolar transistor disposed on the first principal surface side of the semiconductor device at a position corresponding to the convex portion to be electrically connected to the control electrode of the bipolar transistor.