Method for making silicon containing dielectric films

• US 6,967,176 B1
• Filed: 10/13/2003
• Issued: 11/22/2005
• Est. Priority Date: 10/11/2002
• Status: Expired due to Fees

• Current Assignee: University of South Florida (State University System of Florida)
• Original Assignee: University of South Florida (State University System of Florida)
• Inventors: Hoff, Andrew M.
• Primary Examiner(s): Dang, Phuc T.
• Application Number:
  US10/605,609
• Time in Patent Office: 771 Days
• Field of Search: 438/772, 438/778, 438/788, 438/791, 438/792, 438/799, 438/906
• US Class Current: 438/778
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01L 21/049 Conductor-insulator-semiconductor electrodes, e.g. MIS contacts
• CPC Class Codes: Y10S 438/906 Cleaning of wafer as interim step

Abstract

Method and apparatus for forming thin silicon oxide films on silicon carbide substrates utilizing an afterglow thermal reactor. The method of forming thin silicon oxide film includes the steps of loading a silicon carbide substrate within a tube, which tube is heated, and the contents pressure is controlled. An oxidizing gas is then passed through an afterglow reactor source or microwave cavity where the gas achieves an excited state of energy. When the neutral species of the excited gas contact the silicon carbide substrate within the heated region of the the tube, a thin silicon oxide film forms on the substrate, at a faster rate and lower temperature than has been known. The tube contents are maintained at a temperature between 600° C. to 1,200° C., and at a pressure less than 50 torr.

Claims

1. A method of forming thin silicon oxide film, comprising the steps of:

providing a silicon carbide substrate;

providing an afterglow thermal reactor;

employing said afterglow thermal reactor to create an oscillating radio frequency electric field;

exciting an oxidizing gas to an excited state of energy by passing the oxidizing gas through the oscillating radio frequency electric field; and

contacting the substrate with the excited gas at a predetermined temperature.

2. The method of claim 1, further comprising the step of selecting the oxidizing gas from the group consisting of molecular oxygen, atomic oxygen, excited molecular O₂ (singlet delta g state), and nitrogen oxides.

3. The method of claim 1, further comprising the step of maintaining the oxidizing gas at a temperature range between 600°

C. to 1,200°

C.

4. The method of claim 1, further comprising the step of maintaining the oxidizing gas at a pressure less than 50 torr.

5. The method of claim 4, further comprising the step of using a vacuum pump to maintain the pressure.

6. A method of forming thin silicon oxide film, comprising the steps of:

providing a silicon carbide substrate within a tube;

exciting an oxidizing gas to an excited state of energy by passing the oxidizing gas through an oscillating radio frequency electric field; and

contacting the substrate with the excited gas, maintaining the tube and substrate at a temperature range between 600°

C. to 1,200°

C., and at a pressure less than 50 torr.

7. A method of forming thin film of silicon oxide, comprising the steps of:

providing a furnace;

providing a tube;

providing a pump that is in fluid communication with the tube;

positioning a silicon carbide substrate within the tube;

providing an afterglow plasma source;

passing an oxidizing gas through the afterglow plasma source so that the gas achieves an excited state of energy;

adding a secondary gas to the excited gas to produce an excited gas mixture; and

contacting the substrate with the excited gas mixture, using the furnace to maintain the tube at a temperature between 600°

C. to 1,200°

C., and using the pump to maintain the tube at a pressure less than 50 torr.

8. A method of forming thin silicon oxide film, comprising the steps of:

providing a silicon carbide substrate;

providing a microwave cavity;

employing said microwave cavity to create an oscillating radio frequency electric field;

exciting an oxidizing gas to an excited state of energy by passing the oxidized gas through the oscillating radio frequency electric field;

positioning the substrate in remote relation to said microwave cavity;

contacting the substrate held at a predetermined temperature with the excited gas.

9. The method of claim 8, further comprising the step of selecting the oxidizing gas from the group consisting of molecular oxygen, atomic oxygen, excited molecular O₂ (singlet delta g state), and nitrogen oxides.

10. The method of claim 8, further comprising the step of maintaining the oxidizing gas at a temperature range between 600°

C. to 1,200°

C.

11. The method of claim 8, further comprising the step of maintaining the oxidizing gas at a pressure less than 50 torr.

12. The method of claim 8, further comprising the step of using a vacuum pump to maintain the pressure.

13. The method of claim 8, further comprising the step of securing the silicon carbide substrate onto a heated zone.