Method for fabricating semiconductor device capable of adjusting the thickness of gate oxide layer
View Patent ↗The present invention provides a method for fabricating semiconductor device, which is capable of adjusting a gate oxide layer thickness, including: providing a semiconductor substrate; growing a first oxide layer on a surface of the semiconductor substrate; patterning the first oxide layer to expose the first oxide layer corresponding to a gate to be formed; removing the exposed first oxide layer; immersing the substrate into deionized water to grow a second oxide layer; forming a polysilicon layer on the surfaces of the first oxide layer and the second oxide layer; and etching the polysilicon layer to form a gate. The method for fabricating semiconductor device according to the present invention, which is capable of adjusting the thickness of gate oxide layer, can control the thickness of gate oxide layer precisely to satisfy the requirement for different threshold voltages.
1. A method for fabricating semiconductor device, which is capable of adjusting a gate oxide layer thickness, comprising:
providing a semiconductor substrate;
growing a first oxide layer on a surface of the semiconductor substrate;
forming a photoresist layer on a surface of the first gate oxide layer;
patterning the photoresist layer to form a photoresist pattern which defines the position of a gate;
removing the exposed first oxide layer using the photoresist pattern as a mask;
growing a second oxide layer in deionized water at the place where the first oxide layer is removed; and
depositing a polysilicon layer and etching the polysilicon layer to form gate.
2. The method according to claim 1 , wherein the first oxide layer is grown by a furnace thermal oxidation process.
3. The method according to claim 1 , wherein the exposed first oxide layer is removed by using hydrofluoric acid.
4. A method for fabricating semiconductor device, which is capable of adjusting a gate oxide layer thickness, comprising:
providing a semiconductor substrate;
growing a first oxide layer on a surface of the semiconductor substrate;
forming a photoresist layer on a surface of the first gate oxide layer;
patterning the photoresist layer to form a photoresist pattern which defines the position of a gate;
removing the exposed first oxide layer using the photoresist pattern as a mask;
growing a second oxide layer in deionized water at the place where the first oxide layer is removed;
forming a third oxide layer on the surfaces of the first oxide layer and the second oxide layer;
forming a polysilicon layer on the surface of the third oxide layer; and
etching the polysilicon layer to form gate.
5. The method according to claim 4 , further comprising a step of heating the deionized water.
6. The method according to claim 4 , wherein the first oxide layer is grown by a furnace thermal oxidation process.
7. The method according to claim 4 , wherein the first oxide layer at the place corresponding to a gate is removed by using hydrofluoric acid.
8. The method according to claim 4 , wherein the third oxide layer is formed by using the furnace thermal oxidation process or a chemical vapor deposition process.