Low temperature epitaxial growth of germanium islands in active regions of silicon interband tunneling diodes

We incorporate self-assembling Ge islands into Si-based interband tunneling diodes grown by molecular beam epitaxy. The kinetic limitations of low-temperature Ge island formation have been overcome in the growth windows that are required to retain sharp delta-doping profiles in the diode‘s active region. Ge quantum dots are observed for growth temperatures of 360 °C and grown at a rate of 0.125 monolayers per minute. Photoluminescence spectroscopy and annealing experiments indicate three-dimensional carrier localization and phononless radiative recombination, which confirms a dot-like electronic structure. The Ge quantum dots have been incorporated into the active region of delta-doped Si interband tunneling diodes. Room temperature negative-differential-resistance is observed and the electrical characteristics may be tuned by post-growth rapid thermal annealing.