Bottom fixed

`Hello,
Is there a way to fix sidebar when the sidebar bottom reaches bottom of the screen ?
Another words,
there is a sidebar, which has many different widgets social media, forms, etc.
when you scroll down the page, at some point last element of the sidebar appears in viewpoint in the screen bottom
is that possible to freeze sidebar exact at this moment ?
It needs to fill all sidebar side without any spaced under sidebar itself when it fixed.