Sarnoff Corporation has developed thermophotovoltaic (TPV) modules using either Sarnoff grown and processed InGaAsSb/GaSb TPV cells or cells fabricated by our co‐workers. The TPV module fabrication includes substrate design, fabrication and module assembly. The substrate comprises an AlN base plate and Al2O3septa. The septa separate the cells and support metal layers to electrically connect the bottom of a cell to the top of the adjacent septum. A welded gold ribbon connects the septum to the topside of the adjacent cell. The detailed structure of the substrate, as well as the module assembly process, is discussed. TPV modules of 1 cm × 1 cm area with two 1 cm × 0.5 cm cells and 2 cm × 2 cm area with eight cells are fabricated routinely. Alternative approaches to the Al2O3/AlN substrate and ribbon connection have been explored for low‐cost, large‐scale production. Silicon based substrates show promising results. KOH wet etching of silicon produces septa with straight walls having perfect 90‐degree angles at the bottom without fillets. Plated gold forming an “air bridge” to connect the cell busbar and septum has the potential to replace the welded ribbon. Packaging p‐on‐n and n‐on‐p cells alternatively can drastically reduce the complexity of the module structure by facilitating all connections on a planar surface without septa. Sarnoff module technology, when combined with Sarnoff TPV‐cell technology and spectral‐control technologies from other organizations, has led to TPV power‐conversion efficiencies exceeding 17 &percent; [1]. © 2003 American Institute of Physics