Is it true that in .NET the garbage collector gets called when you minimize the program?

I had created a program in C#. That program used about 60-70 MB of my memory. But when I minimized that program, it required less memory, that is, just 10 MB.

When I maximized or came back to that program it used 20 MB...

Why does this happen?

Is it true that garbage collector gets called when you minimize the progam?