Jagged ellipse shapes

Hi there,

I am pretty new to Photoshop. I am trying to create two ellipses but they are jagged and I don't know what I am doing wrong.

Please see screenshot enclosed at resolution 200%.

I used ellipse shapes, and chose in the dropdown menu "shape" (not pixels). Even when I choose pixels and tick the anti aliasing box, it is still jagged. Plus I believe I can't create a pixel shape with borders but no background, right? 

Can someone help me? 

Thanks a lot!