A monolithically integrated lithium thin film battery (10) provides increased areal capacity on a single level (without stacking of multiple cells). The Lithium thin film battery (10) comprises a substrate (12) having a surface (13) textured to comprise a plurality of openings (16) having sides (15) angled between 10 and 80 degrees to the surface (13). A current collector (18) and a cathode (22) are formed on the substrate (12) and within the openings (16). An electrolyte (24) comprising lithium phosphorous oxynitride is formed by physical vapor deposition on the cathode (22), thereby providing a layer on the surface of the cathode (22) and within the openings (16) of the cathode having substantially the same thickness. An anode (26) and a capping layer (28) are then formed on the electrolyte (24).