The present disclosure enables high-volume cost effective production of three-dimensional thin film solar cell (3-D TFSC) substrates. Pyramid-like unit cell structures 16 and 50 enable epitaxial growth through an open pyramidal structure 3-D TFSC embodiments 70, 82, 100, and 110 may be combined as necessary. A basic 3-D TFSC having a substrate, emitter, oxidation on the emitter, and front and back metal contacts allows for simple processing. Other embodiments disclose a selective emitter, selective backside metal contacts, and front-side SiN ARC layers. Several processing methods, including process flows 150, 200, 250, 300, and 350, enable production of these 3-D TFSCs.