My girl will do this when there's no food, no water, no place to potty, or when she wants out. I had been free ranging them during the day and then keeping them in a medium sized Superpet cage at night and she would claw the cage in the morning when she was hungry/thirsty/had to use the litter box. Once we figured these things out and rearranged things (and got a Feisty Ferret), she's quit doing it. She'll dig at the floor in front of the front door of our apartment but that's cause she's nosy.
Anyways, my point is are you 100% sure she's wanting out and not needing something else? I'd would maybe try covering the cage at night too to signal bed time and taking it off when YOU want them to wake up.