Growth of Fluoride Quantum Well Heterostrucutres for Resonant Tunneling Devices on Si Substrates

Heteroepitaxial fluoride structures are candidates of material systems for quantum well devices such as resonant tunneling devices on Si substrates. Resonant tunneling diodes composed of CaF2/CdF2/CaF2 on Si(111) have been demonstrated and they exhibited large potential for high performance quantum effect devices based on high energy barrier and abrupt hetero-interface. However, this material system has significant problem of the pin-hole defects in CaF2 and strong chemical reaction of CdF2 with Si. Fluoride alloys such as CaxCd1-xF2 and CaxMg1-xF2, as well as the post oxidation technique, are effective to overcome these problems.