How unstable can digital supply voltage be?
Update

The problem is most likely not caused by components selection, but by noise from unshielded inductor.

I tried to keep the layout as small as possible and chose 3mm x 3mm unshielded coil.

The layout:



I connected the inductor with some wires and turned it in different direction. The output ripple changed to:



Which gives less than 10mV ripple.