Evaluation of Semiconductor-Metal Atomic Interfaces with High Field Microscopies

用场电子发射和场离子显微镜(FIM)研究了硅超薄膜的生长和硅-金属界面的性质。在金属(W，Mo和Ta)针尖表面气相沉积了几层单层硅后，交替进行了场发射和场离子观测，研究了硅超薄膜状态与功函数的关系。当在50K左右的温度下在W和Mo针尖表面气相沉积Si时，在W和Mo针状试件表面形成了一种具有假致密结构的Si单层，并且所有功函数的值都比W和Mo表面的功函数增加了0.3-0.4 eV。在这种情况下，没有观察到衬底W和Mo表面的原子排列的扰动和缺陷以及硅钨的混合。在Si-W系统中，在850-900K的加热过程中，W{001}、W{111}和W{112}面上特别观察到了早期合金化。根据场离子Ne像和Fowler-Nordheim图的行为，在形成早期硅化物后，W衬底最上面的第三层原子层的场蒸发后，W衬底表面出现了清洁的表面。我们还研究了Si-W混合过程，发现在950K左右的加热过程中，在W衬底的另一个晶格和W{111}面上形成的硅化物相比W衬底上的另一个晶格更深。为了研究分别对应于Si生长和Si-金属界面原子结构的电子态，本工作建立了场发射能谱(Fees)，并继续改进Fees系统以获得高分辨性能。

Silicon ultrathin film growth and silicon-metal interfacial properties were evaluated using field electron emission and field ion microscopies (FEM-FIM). After several monolayrs of Si were vapor-deposited onto the metal (W,Mo and Ta) needle specimen tip surfaces, field emission and field ion observations were made alternately to investigate the correlation between the silicon ultrathin film states and the work function. When Si was vapor-deposited onto the W and Mo tip surfaces at around 50 K,a Si monolayr with a pseudomprphic structure was formed on the W and Mo needle specimen surfaces, and all values of the work function increase 0.3-0.4 eV more than the value of the work function of the W and Mo surfaces. In this case, the disturbance and defects of the atomic arrangements of the substrate W and Mo surfaces and silicontungsten intermixing were not observed. In Si-W system, an alloying in the early stage was especially observed on W {001}, W {111} and W {112} planes in the thermal heating at 850-900 K.After the early stage silicdes were formed, a clean surface of the W substrate appeared after the field evaporation of the topmost third atomic layr of the W substrate, based on the field ion Ne image and the behavior of Fowler-Nordheim plots. Si-W intermixing processes were also investigated, and the silicide phase formed around and on W {111} plane was recognized to forme over the deeper atomic layrs than the another crystall panes of the W substrate in the thermal heating at around 950 K.To investigate the electronic states corresponding the atomic structure of the Si growth and the Si-metal interfaces, respectively, field emission energy spectroscopy (FEES) was constructed at the present work, and the further improvement of the FEES system to high resolution performance has been continued.