Evaluation of Semiconductor-Metal Atomic Interfaces with High Field Microscopies

利用场电子发射和场离子显微镜（FEM-SEM）研究了硅外延膜的生长和硅-金属界面特性。在金属（W、Mo和Ta）针尖表面上气相沉积几层单层Si后，交替进行场发射和场离子观察，研究了Si薄膜状态与功函数之间的相关性。当Si气相沉积到W和Mo针尖表面上时，在W和Mo针样品表面上形成具有赝象结构的Si单层，并且所有的功函数值比W和Mo表面的功函数值增加0.3-0.4 eV。在这种情况下，没有观察到衬底W和Mo表面的原子排列以及硅钨混合的干扰和缺陷。在Si-W系统中，在850-900 K的加热过程中，在W {001}、W {111}和W {112}面上观察到了早期合金化现象。在早期硅化物形成后，W衬底最上面的第三原子层经场蒸发后出现了干净的表面，基于场离子Ne图像和Fowler-Nordheim图的行为。研究了Si与W的混合过程，发现在950 K左右的加热过程中，W {111}面周围和W {111}面上形成的硅化物相比W衬底的其它晶面更深。本文建立了场发射能谱仪（FEES），并对FEES系统进行了进一步的改进，使其具有更高的分辨性能。

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.