Fabrication and characterization of Si quantum dots and SiO2 tunnel barriers grown by a controlled oxidation process

Abstract

The control of the growth of silicon dioxide (SiO2) and the formation of quantum dots (QDs) play an important role in the fabrication of single-electron transistors (SETs). In this work, SET structures were fabricated using a systematic oxidation technique known as the pattern-dependent oxidation (PADOX) process. For comparison, two oxidation processes using conventional furnace and rapid thermal processing (RTP) were used. The oxidation temperature for both oxidation processes was set at 1000°C and the oxygen flow rate in the furnace was set at 1 l min-1. The nanostructures were characterized using AFM, SEM and TEM to determine the quality and the stoichiometry of the Si QDs and the oxides. The oxidation rate using a furnace is 0.36 nm s-1, significantly lower than the RTP value which is 2.16 nm s-1. Meanwhile, the oxygen contents in SiO2 grown by furnace and RTP are approximately the same.