Semiconductor device and method for driving the same

A memory cell comprising:

• a single crystal substrate having a channel formation region;
• an insulating layer over the single crystal substrate;
• a charge holding layer over the insulating layer, the charge holding layer comprising gallium, indium, zinc and oxygen;
• and
• an electrode overlapping with and being direct contact with the charge holding layer.

A memory cell comprising:

• a semiconductor layer comprising a channel formation region;
• an insulating layer over the semiconductor layer;
• a charge holding layer over the insulating layer, the charge holding layer comprising gallium, indium, zinc and oxygen;
• and
• an electrode overlapping with and being direct contact with the charge holding layer.

A memory cell comprising:

• a single crystal substrate having a channel formation region;
• an insulating layer over the single crystal substrate;
• a first metal-containing layer over and being direct contact with the insulating layer;
• a charge holding layer over and being direct contact with the first metal-containing layer, the charge holding layer comprising gallium, indium, zinc and oxygen;
• and
• an electrode overlapping with the charge holding layer and the channel formation region of the single crystal substrate.