Muñoz Eduardo C, Schrebler Ricardo S, Cury Paula K, Suarez Claudio A, Córdova Ricardo A, Gómez Carlos H, Marotti Ricardo E, Dalchiele Enrique A
Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso, Chile.
J Phys Chem B. 2006 Oct 26;110(42):21109-17. doi: 10.1021/jp063246k.
In this study, we examined the influence of illumination and the presence of poly(ethylene oxide) (PEO) as an additive for the copper electrodeposition process onto n-Si(100). The study was carried out by means of cyclic voltammetry (CV) and the potential steps method, from which the corresponding nucleation and growth mechanism (NGM) were determined. Likewise, a morphologic analysis of the deposits obtained at different potential values by means of atomic force microscopy (AFM) was carried out. In a first stage, Mott-Schottky measurements so as to characterize the energetics of the semiconductor/electrolyte interface were made. Also, parallel capacity measurements were carried out in order to determine the surface state density of the substrate. It was found that when PEO concentration is increased, the number of these surface states decreases. The CV results indicated that the presence of PEO inhibits the photoelectrochemical reaction of oxide formation on the surface of the semiconductor. This allows a decrease in the overpotential associated with the electrodeposition process. The analysis of the j/t transients shows that the NGM corresponds to progressive three-dimensional (3D) diffusional controlled (PN3D(Diff)), which was confirmed by the AFM technique. Neither illumination nor the presence of PEO changes the mechanisms. Their influence is in that they diminish the size of the nuclei and the speed with which these are formed, which produces a more homogeneous electrodeposit.
在本研究中，我们考察了光照以及聚环氧乙烷（PEO）作为添加剂对铜在n-Si(100)上进行电沉积过程的影响。该研究通过循环伏安法（CV）和电位阶跃法进行，由此确定了相应的成核与生长机制（NGM）。同样，借助原子力显微镜（AFM）对在不同电位值下获得的沉积物进行了形态分析。在第一阶段，进行了莫特-肖特基测量以表征半导体/电解质界面的能量学。此外，还进行了平行电容测量以确定衬底的表面态密度。结果发现，当PEO浓度增加时，这些表面态的数量会减少。CV结果表明，PEO的存在抑制了半导体表面氧化物形成的光电化学反应。这使得与电沉积过程相关的过电位降低。对j/t瞬态的分析表明，NGM对应于渐进三维（3D）扩散控制（PN3D(Diff)），这一点通过AFM技术得到了证实。光照和PEO的存在均未改变机制。它们的影响在于减小了晶核的尺寸以及晶核形成的速度，从而产生了更均匀的电沉积物。
