Manufacturing method of semiconductor device

摘要

It is an object to provide a manufacturing method of a structure of a thin film transistor including an oxide semiconductor film, in which threshold voltage at which a channel is formed is positive and as close to 0 V as possible. A protective insulating layer is formed to cover a thin film transistor including an oxide semiconductor layer that is dehydrated or dehydrogenated by first heat treatment, and second heat treatment at a temperature that is lower than that of the first heat treatment, in which the increase and decrease in temperature are repeated plural times, is performed, whereby a thin film transistor including an oxide semiconductor layer, in which threshold voltage at which a channel is formed is positive and as close to 0 V as possible without depending on the channel length, can be manufactured.

主权项

1. A manufacturing method of a semiconductor device comprising the steps of:
forming a gate electrode layer over a substrate having an insulating surface; forming a gate insulating layer over the gate electrode layer; forming an oxide semiconductor layer over the gate insulating layer; dehydrating or dehydrogenating the oxide semiconductor layer as a first treatment; forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; forming an insulating layer on the oxide semiconductor layer; and performing a heat treatment as a second treatment, after forming the insulating layer, wherein a thickness of the oxide semiconductor layer is greater than or equal to 5 nm and less than or equal to 200 nm, and wherein a treatment temperature of the second treatment is lower than a treatment temperature of the first treatment.