Resonant tunneling devices on Si(111) substrates using fluoride alloy heterostructures

Resonant tunneling diodes (RTDs) composed of CaF/sub 2/-barrier/CdF/sub 2/-well/CaF/sub 2/-barrier/Si(111) heterostructures are expected to be co-integrated with Si-LSI. The alloy of CaF/sub 2/ and CdF/sub 2/, namely Ca/sub x/Cd/sub l-x/F/sub 2/, was investigated in order to improve characteristics of the RTDs. The barrier height of the RTDs was found to be lowered by using Ca/sub 0.5/Cd/sub 0.5/F/sub 2/ instead of CdF/sub 2/. It was also found that the Cd-rich (x<0.3) alloy could be grown with good crystallinity even at higher temperature than that for pure-CdF/sub 2/. RTDs using the Cd-rich alloy for the well layer exhibited large peak to valley current ratio at room temperature due to the good crystallinity.