A STUDY ON SOI QUANTUM DEVICES WITH VARIABLE FUNCTION BY RESONANT/NON-RESONANT CONTROL IN VERTICAL RESONANT TUNNELING STRUCTURES

为了设计硅/二氧化硅双势垒结构，编制了用逐级势垒近似计算电子隧穿几率来模拟电流-电压特性的程序，并模拟了双势垒结构在温度下，特别是室温下的伏安特性。用内光电子能谱方法测量了金属-氧化物-半导体(MOS)二极管在硅-二氧化硅界面的势垒高度，并首次测定了超薄二氧化硅薄膜的势垒高度。为了实现硅/二氧化硅双势垒结构的量子器件，开发了一种热氧化技术来形成具有高电绝缘性能和可靠性的超薄二氧化硅薄膜，并通过精确控制晶片加热过程中氧化物的生长来降低通过超薄二氧化硅薄膜的MOS二极管的泄漏电流，从而提高了隧道电流的可控性。利用模拟程序对MOS二极管的电流-电压特性进行了分析，结果表明，在超薄区，由于二氧化硅薄膜较薄，电子隧穿的势垒高度较低。为了制作硅/二氧化硅双势垒的垂直结构，开发了一种将一个覆盖着超薄二氧化硅薄膜的晶片与另一个晶片粘接的技术，并制备了具有超薄二氧化硅薄膜埋层氧化物的绝缘体上硅衬底。

A program simulating current-voltage characteristics through tunneling probability calculation of electrons using successive step approximation of energy barriers has been developed so as to design silicon/silicon dioxide double barriers structures, and current-voltage characteristics of double barriers structures at temperatures, and particularly at room temperature, have been simulated. Energy barrier heights at the silicon-silicon dioxide interface of metal-oxide-semiconductor (MOS) diodes fabricated have been measured by internal photoemission, and energy barrier heights of ultrathin silicon dioxide films have been determined for the first time. An thermal oxidation technology forming ultrathin silicon dioxide films with high electrical insulating performance and reliability has been developed in order to realize quantum devices with silicon/silicon dioxide double barriers structures, and the controllability of tunneling current has been enhanced because leak current through MOS diodes with an ultrathin silicon dioxide film can be decreased by the precise control of oxide growth during wafer heating-up processes. The analysis of current-voltage characteristics of MOS diodes fabricated using the simulation program has suggested that the energy barrier height of a silicon dioxide film for the tunneling of electrons is lowered as the film is thin in the ultrathin regime. A technology bonding one wafer covered with an ultrathin silicon dioxide film to another wafer has been developed to fabricate the vertical structure of silicon/silicon dioxide double barriers, and silicon-on-insulator substrates with the buried oxide of an ultrathin silicon dioxide film have been prepared.