Basic Research of UltraーHigh-Speed ThreeーTerminal Electronic Device Using Metal-Insulator Superlattice

点击翻译按钮获取中文摘要

This project is a basic research for realization of three-terminal ultra-highーspeed electronic device using metalーinsulator superlattice and multilayer structures. The main purpose is realization of epitaxial growth of metal-insulator superlattice and ultraーthin layers, establishment of the theory on material properties of this superlattice, and clarification of the basic properties of devices using this material system. Results obtained are summarized as follows.For highーspeed electronic devices, a novel transistor, which introduces metalーinsulator heterostructure and the quantum interference of highーvelocity hot electrons in conduction band of an insulator, was proposed. Possibility of high speed response close to THz of this device was theoretically shown. Also, theoretical analysis was made for the electronic band structure of metal insulator superlattice.Crystal growth of metalーinsulator superlattice and ultraーthin layers was investigated using the ionized cluster beam technique. We chose CaF_2 for the insulator and CoSi_2 for the metal, both of which are lattice matched relatively well to silicon substrate. Condition of epitaxial growth of singleーcrystal flat thin layer (-nm thick) of CoSi_2 on CaF_2/Si(111) was made clear. Using this condition, we fabricated metalーinsulator superlattice.Selective wet chemical etching process necessary to the fabrication of threeーterminal devices with metalーinsulator multilayer structure was found. Using this process, we fabricated the device structure for resistivity measurement of nanometerーthick metal layers in a metalーinsulator multilayer structure, and resistivity of 70 mu OMEGA cm was obtained for ultrathin (2nm thick) CoSi_2 layer. This result shows possibility of ultraーhigh speed device with this material combination.By these results, we obtained possibility of ultraーhighーspeed electronic devices using metalーinsulator multilayer structures and basic knowledge essential to the realization of these devices.