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

本文研究了在细硅点中制备pn结所产生的伪一维量子效应。首先，采用FTIR-ATR和XPS相结合的系统研究了氟(F) /氢(H)端Si（111）表面反应，建立了一种原子层数字蚀刻技术，用于无损伤微细Si点的微细加工。结果表明，在F原子的初始暴露阶段，F原子没有与末端h原子发生反应，而是渗透到亚表面，首先以原子态存在，然后以五配位态存在。然而，更多的F原子暴露导致自发蚀刻，造成粗糙的表面。因此，研究了与Si低反应性的F_2分子在h端Si（111）表面的暴露。在10^5L-10^7L的F_2照射剂量下，SiF的形成达到饱和，从而首次发现了F/Si体系的自限制反应。其次，利用透射电镜研究了离子注入诱导的晶体缺陷，形成了直径小于10nm的Si点pn结。在As和BF_2注入的Si点上均观察到平行于{111}面的位错，在高剂量BF_2注入的Si点上观察到微孪晶。直径小于20nm的硅点无缺陷。这可能是由于缺陷通过表面和Si/SiO_2界面扩散而退火而产生的。最后，利用SIMOX衬底制备了双栅MOS线和SOI线。在4.2K栅极电压变化时，观察到由于库仑阻塞引起的电导振荡。SOI线和MOS线均表现出由于较大线宽的干扰效应而产生的负磁阻和由于足够小宽度的跳变传导而产生的正磁阻。此外，还制备了SOI线的pn结，并在2.5 V和室温下观察到较大的负电阻。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