Method for processing a surface of an SiC semiconductor layer and Schottky contact

• US 6,905,916 B2
• Filed: 05/15/2002
• Issued: 06/14/2005
• Est. Priority Date: 11/15/1999
• Status: Expired due to Term

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Bartsch, Wolfgang, Treu, Michael, Rupp, Roland
• Primary Examiner(s): THAI, LUAN C
• Application Number:
  US10/146,585
• Publication Number:
  US 20020187622A1
• Time in Patent Office: 1,126 Days
• Field of Search: 438/133, 438/570, 438/582, 438/542, 438/583, 438/584, 438/607, 438/689, 438/694, 438/712, 438/745, 438/931
• US Class Current: 438/133
• CPC Class Codes: H01L 21/048 Making electrodes
• CPC Class Codes: H01L 21/0485 Ohmic electrodes
• CPC Class Codes: H01L 21/0495 Schottky electrodes

Abstract

A method for treating a surface on an SiC semiconductor body produced by epitaxy. According to the method, the parts of the epitactic layer that are deposited in the final phase of the epitaxy are removed by etching and a wet chemical treatment is then carried out in order to remove a thin natural oxide on the surface. Alternatively, a metal layer configured as a Schottky contact and/or as an ohmic contact can also be applied to the surface immediately after the removal process.

Claims

1. A surface processing method, which comprises:

providing an epitaxially fabricated SiC semiconductor layer;

subjecting a surface of the SiC semiconductor layer to a removal process;

subsequently wet-chemically processing the surface for removing a natural surface oxide undesirably formed thereon, the wet chemical process being performed directly before an application of a metal layer; and

applying the metal layer functioning as a contact on the surface of the SiC semiconductor layer.

2. The method according to claim 1, which comprises forming the contact as at least one of a Schottky contact and an ohmic contact.

3. The method according to claim 2, which comprises applying the metal layer for the contact to the surface of the SiC semiconductor layer at a given temperature.

4. The method according to claim 3, which comprises setting the given temperature to be more than 100°

C.

5. The method according to claim 1, which comprises performing an etching process selected from the group consisting of a dry etching process and a gas phase etching process as the removal process.

6. The method according to claim 5, which comprises performing at least one of a reactive ion etching and an ion beam etching as the dry etching process.

7. The method according to claim 6, which comprises using a gas mixture having fluorine-containing gases and oxygen in the reactive ion etching.

8. The method according to claim 6, which comprises using a gas mixture having an inert gas and oxygen in the reactive ion etching.

9. The method according to claim 1, which comprises forming the metal layer at least in part as an alloy containing at least one metal selected from the group consisting of titanium, tantalum, and tungsten.

10. The method according to claim 1, which comprises performing the removal process in at least two stages.

11. The method according to claim 10, which comprises carrying out an ion implantation with a subsequent annealing process between the at least two stages.