Manufacturing method of semiconductor device
A problem in the conventional technique is that metal contamination on a silicon carbide surface is not sufficiently removed in a manufacturing method of a semiconductor device using a monocrystalline silicon carbide substrate. Accordingly, there is a high possibility that the initial characteristics of a manufactured silicon carbide semiconductor device are deteriorated and the yield rate is decreased. Further, it is conceivable that the metal contamination has an adverse affect even on the long-term reliability of a semiconductor device. In a manufacturing method of a semiconductor device using a monocrystalline silicon carbide substrate, there is applied a metal contamination removal process, on a silicon carbide surface, including a step of oxidizing the silicon carbide surface and a step of removing a film primarily including silicon dioxide formed on the silicon carbide surface by the step.
1. A manufacturing method of a semiconductor device having
a conductive monocrystalline silicon carbide substrate,
an epitaxial layer having a drift layer of a first conductive type,
a layer primarily including a metal silicide formed on a back side of the monocrystalline silicon carbide substrate,
an electrode formed on a surface of the epitaxial layer, said method comprising:
a first step of forming an oxide film by oxidizing the back side of the monocrystalline silicon carbide substrate prior to formation of the layer primarily including the metal silicide;
a second step of removing the oxide film; and
a third step of forming the layer primarily including the metal silicide after the second step.
2. The manufacturing method according to claim 1 ,
wherein the oxidation is performed by an oxygen plasma process, a thermal oxidation, or an oxidation using ozone.
3. The manufacturing method according to claim 1 ,
wherein the oxide film is removed by dipping into an etching solution containing hydrofluoric acid.