The fabrication of super atom structure using Si based self-assembled quantum dots and its electron state control

通过改变VHF功率、H_2等离子体气压和衬底温度，我们证明了在SiH_4-LPCVD前进行远程H_2等离子体处理，可以将Si的成核密度控制在100 × 10 ~（-1）<11>cm ~ 2<-2>。远程Ar等离子体和随后的H_2等离子体的组合对于实现面密度为10^ cm ~ 2量级的均匀尺寸分布的Si点是相当有效<11>的<-2>。LPCVD和远程等离子体表面处理（包括远程等离子体氧化）相结合的方法是一种很有前途的制备由Si-QD和SiO_2中间层组成的多层堆叠结构的方法。从观察。多层Si-QD在SiO_2中的充放电特性。高密度Si量子点电荷态的时间衰减不仅可以通过底部隧道氧化层的放电过程来表征， 关于我们 为了控制自组装硅量子点（Si-QD）的价态，在由纯SiH_4热分解生成的SiO_2上形成量子点的过程中，通过脉冲注入1%B_2H_6或用He稀释的PH_3，对Si-QD进行硼或磷掺杂。利用原子力显微镜探针技术研究了B和P掺杂硅量子点的电子充放电过程。分别施加+0.5V和+0.2V的尖端偏压，观察到从B和P掺杂的Si量子点中提取一个电子所对应的电势变化。另一方面，对于具有与掺杂的Si-QD几乎相同的尺寸的纯Si-QD，引起几乎相同量的电势变化的尖端偏压高达100 V。从B和P掺杂的Si-QD的电子提取可以解释为从离子化的B受体产生的电子的发射和由离子化的P供体引起的传导电子的发射，这不同于从未掺杂的Si-QD的价电子的发射。此外，正电荷态的保留特性的改善被证实，特别是对于P掺杂的Si量子点。少

We have demonstrate that the Si nucleation density with remote H_2 plasma treatments just before SiH_4-LPCVD can be controlled up to 〜1x10^<11>cm^<-2> by changing the VHF power, the H_2 plasma pressure and the substrate temperature. The combination of the remote Ar plasma and subsequent H_2 plasma is quite effective to achieve a uniform size distribution of Si dots with an areal density of the order of 10^<11>cm^<-2>. This technique is very promising for the fabrication of multiple stacked structures of Si-based dots embedded in Si0_2.The combination of LPCVD and remote plasma surface treatments including remote plasma oxidation is a promising method to fabricate multiply-stacked structures consisting of Si-QDs and ultrathin SiO_2 interlayers. From observing the. charging and discharging characteristics of multiply-stacked Si-QDs in Si0_2. The temporal decay of charged states of high density Si-QDs can be characterized by not only discharging process through the bottom tunnel oxide but … More also the neutralization due to carrier recombination.For valency control of self-assembled Si quantum dots (Si-QDs), boron or phosphorous doping to Si-QDs was performed by a pulse injection of 1% B_2H_6 or PH_3 diluted with He during the dot formation on thermally-grown Si0_2 from thermal decomposition of pure SiH_4. Electron charging to and discharging from B or P-doped Si-QDs were studied to characterize their electronic charged states by a Kelvin probe technique using Rh-coated AFM tip. The potential changes corresponding to the extraction of one electron from the B and P-doped Si-QDs were observed by applying tip biases of +0.5V and +0.2V, respectively. On the other hand, for pure Si-QDs with almost the same size as doped Si-QDs, the tip bias causing almost the same amount of the potential change was as high as 〜1V. The electron extraction from B and P-doped Si-QDs can be interpreted in terms of the emission of an electron generated from ionized B acceptor and of a conduction electron caused by ionized P donor, being different from the emission of valence electrons from undoped Si-QDs. Also, an improvement of retention characteristics of positively-charged states was confirmed especially for P-doped Si-QDs. Less