A method to fabricate a three dimensional memory structure may include creating a stack of layers including a conductive source layer, a first insulating layer, a select gate source layer, and a second insulating layer, and an array stack. A hole through the stack of layers may then be created using the conductive source layer as a stop-etch layer. The source material may have an etch rate no faster than 33% as fast as an etch rate of the insulating material for the etch process used to create the hole. A pillar of semiconductor material may then fill the hole, so that the pillar of semiconductor material is in electrical contact with the conductive source layer.