Transistor with stacked oxide semiconductor films

摘要

Objects are to provide a semiconductor device for high power application in which a novel semiconductor material having high productivity is used and to provide a semiconductor device having a novel structure in which a novel semiconductor material is used. The present invention is a vertical transistor and a vertical diode each of which has a stacked body of an oxide semiconductor in which a first oxide semiconductor film having crystallinity and a second oxide semiconductor film having crystallinity are stacked. An impurity serving as an electron donor (donor) which is contained in the stacked body of an oxide semiconductor is removed in a step of crystal growth; therefore, the stacked body of an oxide semiconductor is highly purified and is an intrinsic semiconductor or a substantially intrinsic semiconductor whose carrier density is low. The stacked body of an oxide semiconductor has a wider band gap than a silicon semiconductor.

主权项

1. A semiconductor device comprising:
a transistor comprising:
a stacked body comprising:
a first oxide semiconductor film; anda second oxide semiconductor film on and in contact with the first oxide semiconductor film;a gate insulating film covering the first oxide semiconductor film and the second oxide semiconductor film; anda gate electrode over the gate insulating film and facing at least a side surface of the second oxide semiconductor film, wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises indium and zinc.