Electronic Structures and the Mechanical Stability of Ultra-thin Metal Films on the Semiconductor Surface and the Effect of Internal Stress on Them

在Si（111）晶面上沉积了厚度为1 ~ 10 nm的铟（In）、铅（Pb）和银（Ag）薄膜，用分子束和溅射方法在碳和玻璃表面制备了非晶薄膜，并利用反射高能电子衍射（RHEED）和电子能量损失谱（ELS）研究了这两种非晶薄膜的表面形貌。三维晶体结构和电子状态。在晶体表面上建立了In和Pb随厚度和温度变化的相图，在损耗谱中，外延生长的薄膜中可以观察到明确的价电子或芯电子跃迁，但随着结晶度的降低，这些跃迁变得模糊不清。金属膜在半导体表面有岛状生长的趋势，在电子显微镜上分析了其尺寸和厚度分布。在溅射沉积的薄膜中观察到明显的动力学效应和充电效应，通过内应力和划痕试验测量了薄膜在实际条件下的耐久性，考察了不同膜/基组合和制备条件的影响。内应力不直接影响粘附强度，但由于表面污染和粗糙度，观察到的强度的分散性变得很大。对衬底施加正偏压导致温度升高，并且岛状结构接近于通过真空沉积获得的岛状结构。当施加负偏压时，岛状结构变得小但均匀。建立了一种通过在衬底上施加适当的电压来控制晶体取向的方法。

Thin films of indium (In), lead (Pb) and silver (Ag) whose thickness ranges from 1 to 10 nanometers, have been deposited on crystalline surface of Si(111), amorphous surfaces of carbon and glass by using molecular beam methods and sputtering.Reflection high energy electron diffraction (RHEED) and electron energy loss spectroscopy (ELS) were employed to study the two-dimensional crystalline structure and the electron states. On the crystalline surface phase diagrams of In and Pb have been established concerning the thickness and the temperature.In the loss spectrum, definite transitions from valence or core electrons could be observed in films growing epitaxially but they became ambiguous as crystallinity decreased. Metal films have a tendency to grow in island form on the semiconductor surface, the size and interisland distributions were analyzed on the electron microphotographs. The kinetic effects and the effect of charge up were observed clearly in the sputter deposited thin films.The durability of thin films under the practical condition was measured from the internal stress and the scratch test.Various combinations of films/substrate and the effect of the preparation conditions were examined. Internal stress does not effect directly on the adhesion strength but the scatter of observed strength becomes great due to surface contamination and roughness. Applying positive bias to the substrate results in a temperature rise and the island structure is close to those obtained by vacuum deposition. When negative bias is applied, island structure becomes small but uniform. A technique to control the orientation of the craystallite structure by applying a proper voltage to substrate has been established.