Fabrication of Fine Si Dot PN Junction pn junction and its Pseudo-One Dimensional Quantum Effects

这项研究是为了阐明在细小的硅点上制作的pn结产生的伪一维量子效应。首先，利用FTIR-ATR和XPS相结合的系统研究了氟(F)/氢(H)终止的Si(111)表面反应，建立了原子层数字刻蚀技术，用于微细硅点的无损微细加工。结果表明，在F原子的初始暴露阶段，F原子没有与终止的-H原子发生反应而穿透到次表面，首先以原子态存在，然后以五配位态存在。然而，F原子暴露过多导致了自发刻蚀，导致表面粗糙。因此，我们研究了与硅反应活性较低的F_2分子在H-端基Si(111)表面的暴露情况。在F_2辐照剂量为10^5L-10^7L时，SiF的形成达到饱和，从而首次发现了F/Si体系的自限反应。接下来，水晶清晰度…为了形成直径小于10 nm的硅点pn结，用透射电子显微镜研究了离子注入引起的更多的ECTS。在硅点中观察到As和BF_2两种注入情况下都有平行于{111}面的位错，以及高剂量BF_2注入时的微孪晶。直径小于20 nm的硅点未产生缺陷。这可能是由于缺陷通过表面和Si/SiO_2界面的扩散而退火所致。最后，制作了采用SIMOX衬底的双栅MOS线和SOI线。在4.2K时，观察到了MOS丝栅电压变化的库仑阻塞引起的电导振荡。对于较大的线宽，SOI和MOS线都表现出负的磁阻效应，而对于足够小的线宽，则表现出正的磁阻效应。此外，在SOI线中制作了精细的pn结，在2.5V和室温下观察到了较大的负阻。较少

This study was carried out to elucidate the pseudo-one dimensional quantum effects generated from a pn junction fabricated in a fine Si dot. First, fluorine (F) /hydrogen (H) -terminated Si (111) surface reaction was studied employing a combined system of FTIR-ATR and XPS in order to establish an atomic layr digital etching which was used for a damageless microfabrication of fine Si dots. It was made clear that at the initial exposure stage of F atoms, F atoms penetrate into the subsurface without their reaction with the terminated-H atoms, existing as an atomic state first, subsequently as a five-coordinated state. However, more exposure of F atoms led to the spontaneous etching, causing the rough surface. Hence, the exposure of F_2 molecule of low reactivity with Si to the H-terminated Si (111) surface was investigated. The formation of SiF was saturated at the F_2 exposure dose of 10^5L-10^7L Thus, the self-limiting reaction was first found out for the F/Si system. Next, crystal def … More ects induced by an ion implantation was studied by TEM for formation of the Si dot pn junction with a diameter less than 10nm. A dislocation parallel to the {111} plane for both cases of As and BF_2 implantations, and a micro-twin for high dose BF_2 were observed in Si dots. No defects was caused for the Si dot with a diameter less than 20nm. This may resulted form annealing-out of defects via their diffusion through surfaces and Si/SiO_2 interfaces. Finally, the double gate MOS wire and teh SOI wire using a SIMOX substrate were fabricated. The conductance oscillation due to the Coulomb blockade was observed at 4.2K for gate voltage changes in the MOS wire. Both the SOI and the MOS wires demonstrated the negative magneto-resistance due to an interference effect for the larger wire width and the positive one due to a hopping conduction for sufficiently small width. In addition, the fine pn junction in the SOI wire was fabricated and the large negative resistance was observed at 2.5 V and a room temperature. Less