Why does not load SOS.dll in VS 2013

The SOS Debugging Extension that I use in VS2010, but now cannot use in VS2013. I guess, I have to any update or some stuff install for VS2013, right?

I try to like below in the Immediate Window;

.load sos

Invalid expression term '.'

.load C:\Windows\Microsoft.NET\Framework\v4.0.30319\SOS.dll

Unexpected character '\'

.load "C:\Windows\Microsoft.NET\Framework\v4.0.30319\SOS.dll"

Unrecognized escape sequence

.load C:\Windows\Microsoft.NET\Framework\v4.0.30319\SOS.dll

Unexpected character '\'

.load C:/Windows/Microsoft.NET/Framework/v4.0.30319/SOS.dll

Invalid expression term '.'