Systems and methods for forming an encapsulated device include a hermetic seal which seals an insulating environment between two substrates, one of which supports the device. The hermetic seal is formed by an alloy of two metal layers, one deposited on a first substrate and the other deposited on the second substrate, along with a raised feature formed on the first or the second substrate. At least one of the metal layers may be deposited conformally over the raised feature. The raised feature penetrates the molten material of the first or the second metal layers during formation of the alloy, and produces a spectrum of stoichiometries for the formation of the desired alloy, as a function of the distance from the raised feature. At some distance from the raised feature, the proper ratio of the first metal to the second metal exists to form an alloy of the preferred stoichiometry.