Fabrication of hole resonant tunneling diodes with nanometer order heterostructures of Si/strained Si_1-xGe_x epitaxially grown on Si(100)

Hole resonant tunneling diodes with Si/strained Si_1-x(Ge _x heterostructures epitaxially grown on Si(100) were fabricated and improvement of the negative differential conductance characteristics was explored by reducing thickness of Si barriers and Si_1-xGe_x quantum well into a few nanometer order. It was clearly shown that, by reducing the Si barrier thickness down to 2 nm, high peak current density above a few kA/cm² can be obtained under a peak-to-valley ratio of abcut 2 at 11 K. From the temperature dependence of the peak and valley currents, it is suggested that local introduction of higher Ge fraction effectively suppresses increase of valley current at higher temperatures.