Semiconductor device and manufacturing method thereof
An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.
1. A method of manufacturing a semiconductor device comprising the steps of:
forming a gate electrode over a substrate;
forming a first insulating film comprising silicon nitride over the gate electrode;
forming a second insulating film comprising silicon and oxygen over the first insulating film;
forming an oxide semiconductor film over the gate electrode with the first insulating film and the second insulating film interposed therebetween, the oxide semiconductor film including a channel formation region;
forming a source electrode and a drain electrode over the oxide semiconductor film, wherein part of the oxide semiconductor film between the source electrode and the drain electrode is etched; and
forming a third insulating film over the oxide semiconductor film, the source electrode and the drain electrode, the third insulating film comprising silicon oxide and being in contact with at least a portion of the oxide semiconductor film,
wherein each of the source electrode and the drain electrode comprises a nitride of a metal selected from the group consisting of Al, W, Mo, Ta, and Ti, and
wherein the oxide semiconductor film comprises gallium, zinc and indium.
2. The method according to claim 1 , wherein each of the first insulating film and the oxide semiconductor film is formed by sputtering.
3. The method according to claim 1 , further comprising the step of heating the oxide semiconductor film at a temperature 250° C. to 570° C. in order to crystallize at least a portion of the oxide semiconductor film.
4. The method according to claim 1 , further comprising the step of crystallizing at least a portion of the oxide semiconductor film by laser irradiation.
5. The method according to claim 1 , further comprising the step of crystallizing at least a portion of the oxide semiconductor film by rapid thermal annealing using light.
6. A method of manufacturing a semiconductor device comprising the steps of:
forming a gate electrode over a substrate;
forming a first insulating film comprising silicon oxide over the gate electrode;
forming an oxide semiconductor film over the gate electrode with the first insulating film interposed therebetween, the oxide semiconductor film including a channel formation region;
forming a source electrode and a drain electrode over the oxide semiconductor film, wherein part of the oxide semiconductor film between the source electrode and the drain electrode is etched; and
forming a second insulating film over the oxide semiconductor film, the source electrode and the drain electrode,
wherein the second insulating film is in contact with a surface of the oxide semiconductor film,
wherein each of the source electrode and the drain electrode comprises a nitride of a metal selected from the group consisting of Al, W, Mo, Ta, and Ti, and
wherein the oxide semiconductor film comprises gallium, zinc and indium.
7. The method according to claim 6 , wherein each of the first insulating film and the oxide semiconductor film is formed by sputtering.
8. The method according to claim 6 , further comprising the step of heating the oxide semiconductor film at a temperature 250° C. to 570° C. in order to crystallize at least a portion of the oxide semiconductor film.
9. The method according to claim 6 , further comprising the step of crystallizing at least a portion of the oxide semiconductor film by laser irradiation.
10. The method according to claim 6 , further comprising the step of crystallizing at least a portion of the oxide semiconductor film by rapid thermal annealing using light.