Semiconductor device, RFID tag using the same and display device

A semiconductor device having a first thin-film transistor and a second thin-film transistor each comprising a gate insulating film, a gate electrode, a channel layer, a source electrode, and a drain electrode which are formed over a main surface of a substrate, wherein

• the channel layer of each of the first and second thin-film transistors is made of oxide semiconductor containing at least In and oxygen and further containing one or more types of elements among Zn, Cd, Al, Ga, Si, Sn, Ce, and Ge;
• the channel layer of the first thin-film transistor has, in a region nearest to the gate electrode, a high concentration region with a maximum In concentration 30 at % or more higher than other regions of the channel layer;
• the channel layer of the second thin-film transistor has, in a region remotest from the gate electrode, a high concentration region with a maximum In concentration 30 at % or higher than the other regions of the channel layer;
• and
• film thickness of the high concentration region of each of the first and second thin-film transistors is 20 nm or less.

An RFID tag having an antenna section and an IC chip,

• the IC chip having a thin-film transistor comprising a gate insulating film, a gate electrode, a channel layer, a source electrode, and a drain electrode which are formed over a main surface of a substrate, wherein
• the channel layer of the thin-film transistor is made of oxide semiconductor containing at least In and oxygen and further containing one or more types of elements among Zn, Cd, Al, Ga, Si, Sn, Ce, and Ge;
• a portion of the channel layer has a high concentration region with a maximum In concentration 30 at % or higher than other regions of the channel layer;
• and
• film thickness of the high concentration region is 20 nm or less.

A display device having a thin-film transistor comprising a gate insulating film, a gate electrode, a channel layer, a source electrode, and a drain electrode which are formed over a main surface of a substrate, wherein

• the channel layer of the thin-film transistor is made of oxide semiconductor containing at least In and oxygen and further containing one or more types of elements among Zn, Cd, Al, Ga, Si, Sn, Ce, and Ge;
• a portion of the channel layer has a high concentration region with a maximum In concentration 30 at % or higher than other regions of the channel layer;
• and
• film thickness of the high concentration region is 20 nm or less.