A rapid melt growth process for forming interband Esaki tunnel junctions on Ge is shown. The process uses a phosphorus spin-on diffusant and rapid thermal annealing to form the side of the junction, while for the side, a deposited aluminum film serves both as an acceptor dopant source and a melt for epitaxial regrowth of . The current density in these junctions depends strongly on the peak temperature of the melt and ranges between a few to over . The use of a silicon nitride microcrucible improves the surface morphology by confining the melt. Record forward peak current density of and reverse interband tunnel current density of is achieved at a peak temperature of approximately .