Semiconductor device and display device including the same

A semiconductor device comprising:

• a transistor including:
• an insulating film;
• a first conductive film;
• a second conductive film;
• a third conductive film;
• and
• an oxide semiconductor film,
• wherein the first conductive film includes a region in contact with the oxide semiconductor film,
• wherein the second conductive film includes a region in contact with the oxide semiconductor film,
• wherein the third conductive film includes a region that overlaps with the oxide semiconductor film,
• wherein the insulating film is provided between the third conductive film and the oxide semiconductor film,
• wherein the transistor includes:
• a region where a maximum value of field-effect mobility of the transistor at a gate voltage of higher than 0 V and lower than or equal to 10 V is larger than or equal to 40 cm2/Vs and smaller than 150 cm2/Vs;
• a region where threshold voltage is higher than or equal to −1 V and lower than or equal to 1 V;
• a region where an S value is smaller than 0.3 V/decade;
• and
• a region where off-state current is lower than 1×10−12 A/cm2, and
• wherein μFE(max)/μFE(Vg=2V) is larger than or equal to 1.5 and smaller than 3, where μFE(max) represents the maximum value of the field-effect mobility of the transistor and μFE(Vg=2V) represents a value of the field-effect mobility of the transistor at a gate voltage of 2 V.

A semiconductor device comprising:

• a transistor including:
• an insulating film;
• a first conductive film;
• a second conductive film;
• a third conductive film;
• and
• an oxide semiconductor film,
• wherein the first conductive film includes a region in contact with the oxide semiconductor film,
• wherein the second conductive film includes a region in contact with the oxide semiconductor film,
• wherein the third conductive film includes a region that overlaps with the oxide semiconductor film,
• wherein the insulating film is provided between the third conductive film and the oxide semiconductor film,
• wherein the transistor includes:
• a region where a maximum value of field-effect mobility of the transistor at a gate voltage of higher than 0 V and lower than or equal to 10 V is larger than or equal to 10 cm2/Vs and smaller than 100 cm2/Vs;
• a region where threshold voltage is higher than or equal to −1 V and lower than or equal to 1 V;
• a region where an S value is smaller than 0.3 V/decade;
• and
• a region where off-state current is lower than 1×10−12 A/cm2, and
• wherein μFE(max)/μFE(Vg=2V) is larger than or equal to 3 and smaller than 10, where μFE(max) represents the maximum value of the field-effect mobility of the transistor and μFE(Vg=2V) represents a value of the field-effect mobility of the transistor at a gate voltage of 2 V.