Reaction Steps and Mechanism for Chemical Vapor Deposition of Tungsten

PIs提出了一项综合研究计划，研究六氟化钨（WF6）与硅/二氧化硅表面之间的化学气相沉积（CVD）反应。了解这种反应可以帮助半导体加工公司制造超大规模集成（VLSI），超大规模集成（ULSI）和晶圆规模集成（WSI）芯片。钨具有潜在的用途，因为(1)它的电磁弹性，(2)低电阻率，(3)高熔点，(4)热膨胀系数接近硅。钨的选择性及其电学和物理特性使其适用于许多VLSI大型电路应用，因为选择性沉积的钨膜为浅结提供高可靠性，低电阻和低成本的接触屏障。随着器件规模的减小，钨作为多层金属化互连的潜在用途将增加。这对于ULSI和WSI技术的进步至关重要。钨的化学气相沉积具有低温加工、选择性、无辐射损伤、保形覆盖等优点。为了更好地了解硅和WF6之间的气固反应，pi计划在超高真空中使用俄歇电子能谱（AES），温度程序反应（TPR）和高分辨率电子能量损失能谱（HREELS）。AES允许对表面进行分析以确定其元素组成。TPR给出了反应中每种气体产物形成的速率。HREELS测定吸附物质中存在的化学键。这种气体产物、吸附物质和元素表面组成的测量组合应该提供反应过程的完整图像。

The PIs propose a comprehensive research program to study the chemical vapor deposition (CVD) reaction between tungsten hexafluoride (WF6) and silicon/silicon dioxide surfaces. Understanding of this reaction could help semiconductor processing companies in the manufacture of very large scale integration (VLSI), ultra large scale integration (ULSI), and wafer scale integration (WSI) chips. Tungsten has potential usage because of (1) its resilience to electromagnetism, (2) low resistivity, (3) high melting point, and (4) a thermal coefficient of expansion that is close to silicon. The selective nature of tungsten along with its electrical and physical properties makes it suitable for many VLSI large circuit applications because selectively-deposited tungsten films provide highly reliable, low resistance, and low cost contact barriers for shallow junctions. As the scale of devices decreases, tungsten's potential use will increase as an interconnect for multilevel metallization. This will be essential for advances in ULSI and WSI technology. CVD of tungsten has the advantages of low temperature processing, selectivity, radiation-damage-free deposition and conformal coverage. To obtain a better understanding of the gas-solid reaction between silicon and WF6, the PIs plan to use a Auger electron spectroscopy (AES), temperature- programmed reaction (TPR), and high resolution electron energy loss spectroscopy (HREELS) in ultrahigh vacuum. AES permits analysis of a surface to determine its elemental composition. TPR gives the rate that each gaseous product forms during reaction. HREELS determines chemical bonds present in adsorbed species. This combination of measurements of gaseous products, adsorbed species, and elemental surface composition should provide a complete picture of the reaction process.