There are two parts to build fusion carbon metal interconnects. First are the fusing metals/alloys, typically in the Martensite phase and lacking carbon. Second are carbonized materials that have carbon infused. These carbonized materials may be referred to as carbon donating materials. Both parts can be interchanged as the substrate or mounted component, or the parts can form linear interface connections. The finished interfaces have very low electrical resistance and/or zero interface electrical resistance. The interconnect circuit topography materials and connections are endless and is dependent on circuit design. One example of such interface is a solderless thermoelectric device capable of use at higher operating temperatures as compared to conventional low temperature solders thus allowing the thermoelectric device to be used in a Seebeck device, for example. The thermoelectric device forms a fusion layer between a copper metal layer and a semiconductor wafer layer to create a true metallurgical bond.