NOVELTY - A thin film solar cell base structure (10) comprises flexible conductive substrate (11), insulating buffer layer, contact layer, and absorber layer (12). The conductive substrate has top surface including protruded and recessed surface portions. The insulating buffer layer is on top surface of the flexible conductive substrate. The insulating buffer layer is high resistivity layer that fills the recessed surface portions while partially exposing some of the protruded surface portions.    USE - Base structure for thin film solar cell (claimed) such as cadmium tellurium solar cells and Group IBIIIAVIA thin film solar cells.    ADVANTAGE - The base structure improves solar cell device conversion efficiency and yields, and reduces surface roughness by coating surface with a thin silicon dioxide which fills the cavities and recesses around the protrusions.    DETAILED DESCRIPTION - A thin film solar cell base structure (10) comprises flexible conductive substrate (11), insulating buffer layer, contact layer, and absorber layer (12). The conductive substrate has top surface including protruded and recessed surface portions. The insulating buffer layer is on top surface of the flexible conductive substrate. The insulating buffer layer is high resistivity layer that fills the recessed surface portions while partially exposing some of the protruded surface portions. The contact layer is on insulating buffer layer and on some of the protruded surface portion so that the contact layer makes physical and electrical contact with the protruded surface portion. The absorber is on the contact layer. An INDEPENDENT CLAIM is included for manufacturing thin film solar cell base structure comprising providing conductive substrate, depositing high resistivity material to form buffer layer on top surface of conductive substrate, and depositing conductive material on buffer layer and on some of the protruded surface portions. The high resistivity material covers the flat surface portions while leaving partially exposed some of the protruded surface portions.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross sectional view of the solar cell using Group IBIIIAVIA absorber layer.    Thin film solar cell base structure (10)    Substrate (11)    Absorber layer (12)    Transparent conductive layer (13)    Protrusions (15)    Pits (16)