Plasma CVD apparatus, method for manufacturing microcrystalline semiconductor layer, and method for manufacturing thin film transistor
View Patent ↗As an electrode area of a plasma CVD apparatus is enlarged, influence of the surface standing wave remarkably appears, and there is a problem in that in-plane uniformity of quality and a thickness of a thin film formed over a glass substrate is degraded. Two or more high-frequency electric powers with different frequencies are supplied to an electrode for producing glow discharge plasma in a reaction chamber. With glow discharge plasma produced by supplying the high-frequency electric powers with different frequencies, a semiconductor thin film or an insulating thin film is formed. High-frequency electric powers with different frequencies (different wavelengths), which are superimposed on each other, are applied to an electrode in a plasma CVD apparatus, so that increase in plasma density and uniformity for preventing effect of surface standing wave of plasma are attained.
1. A method for manufacturing a thin film transistor comprising:
supplying a reaction gas in a reaction chamber;
applying a first high-frequency electric power of 3 MHz to 30 MHz inclusive and a second high-frequency electric power of higher than 30 MHz and 300 MHz or lower, which are superimposed on each other, to an electrode provided in the reaction chamber, so that glow discharge plasma is produced;
depositing a microcrystalline semiconductor layer over a substrate mounted in the reaction chamber; and
forming the thin film transistor including the microcrystalline semiconductor layer as a semiconductor layer,
wherein the electrode has an almost rectangular shape including at least one side of 2000 mm or longer.
2. A method for manufacturing a thin film transistor according to claim 1 ,
wherein a rare gas or a combination of a rare gas and hydrogen is supplied before the microcrystalline semiconductor layer is deposited, and a surface where the microcrystalline semiconductor layer is deposited is subjected to plasma treatment.
3. A method for manufacturing a thin film transistor according to claim 1 ,
wherein the reaction gas is one of the combinations of silane and hydrogen; silane and a rare gas; and silane, hydrogen, and a rare gas.
4. A method for manufacturing a thin film transistor comprising:
supplying a first reaction gas to a reaction chamber;
producing glow discharge plasma by applying a first high-frequency electric power of 3 MHz to 30 MHz inclusive and a second high-frequency electric power of higher than 30 MHz and 300 MHz or lower, which are superimposed on each other, to an electrode provided in the reaction chamber, so that a microcrystalline semiconductor layer is deposited;
supplying a second reaction gas to the reaction chamber;
depositing an amorphous semiconductor layer by blocking the second high-frequency electric power; and
forming the thin film transistor including the microcrystalline semiconductor layer and the amorphous semiconductor layer as a semiconductor layer,
wherein the electrode has an almost rectangular shape including at least one side of 2000 mm or longer.
5. A method for manufacturing a thin film transistor according to claim 4 ,
wherein a rare gas or a combination of a rare gas and hydrogen is supplied before the microcrystalline semiconductor layer is deposited, and
wherein a surface where the microcrystalline semiconductor layer is deposited is subjected to plasma treatment.
6. A method for manufacturing a thin film transistor according to claim 4 ,
wherein the first reaction gas is one of the combinations of silane and hydrogen; silane and a rare gas; and silane, hydrogen, and a rare gas.
7. A method for manufacturing a thin film transistor comprising:
supplying a first reaction gas to a reaction chamber;
producing glow discharge plasma by applying a first high-frequency electric power of 3 MHz to 30 MHz inclusive and a second high-frequency electric power of higher than 30 MHz and 300 MHz or lower, which are superimposed on each other, to an electrode provided in the reaction chamber, so that a microcrystalline semiconductor layer is deposited;
supplying a second reaction gas to the reaction chamber;
depositing an amorphous semiconductor layer by blocking the second high-frequency electric power and continuing the application of the first high-frequency electric power; and
forming the thin film transistor including the microcrystalline semiconductor layer and the amorphous semiconductor layer as a semiconductor layer,
wherein the electrode has an almost rectangular shape including at least one side of 2000 mm or longer.
8. A method for manufacturing a thin film transistor according to claim 7 ,
wherein a rare gas or a combination of a rare gas and hydrogen is supplied before the microcrystalline semiconductor layer is deposited, and
wherein a surface where the microcrystalline semiconductor layer is deposited is subjected to plasma treatment.
9. A method for manufacturing a thin film transistor according to claim 7 ,
wherein the first reaction gas is one of the combinations of silane and hydrogen; silane and a rare gas; and silane, hydrogen, and a rare gas.
10. A method for manufacturing a thin film transistor comprising:
supplying a first reaction gas in a reaction chamber;
applying a first high-frequency electric power of 3 MHz to 30 MHz inclusive and a second high-frequency electric power of higher than 30 MHz and 300 MHz or lower, which are superimposed on each other, to an electrode provided in the reaction chamber, so that glow discharge plasma is produced;
depositing a semiconductor layer over a substrate mounted in the reaction chamber; and
forming the thin film transistor including the semiconductor layer,
wherein the electrode has an almost rectangular shape including at least one side of 2000 mm or longer.
11. A method for manufacturing a thin film transistor according to claim 10 ,
wherein a rare gas or a combination of a rare gas and hydrogen is supplied before the microcrystalline semiconductor layer is deposited, and a surface where the semiconductor layer is deposited is subjected to plasma treatment.
12. A method for manufacturing a thin film transistor according to claim 10 ,
wherein the semiconductor layer is one selected from the group consisting of an amorphous silicon layer, an amorphous silicon germanium layer, an amorphous silicon carbide layer, a microcrystalline silicon germanium layer, a microcrystalline silicon carbide layer.