Methods for direct bonding in semiconductor die manufacturing

A method for bonding semiconductor dies, resulting semiconductor devices, and associated systems and methods are disclosed. In some embodiments, the method includes depositing a first material on the first semiconductor die. The first material has a first outer surface and a first chemical composition at the first outer surface. The method also includes depositing a second material on the second semiconductor die. The second material has a second outer surface and a second chemical composition at the second outer surface that is different from the first chemical composition. The method also includes stacking the dies. The second outer surface of the second semiconductor die is in contact with the first outer surface of the first semiconductor die in the stack. The method also includes reacting the first outer surface with the second outer surface. The reaction causes the first outer surface to bond to the second outer surface.