不同金属/氢终端金刚石（100）界面结构的第一性原理研究

金刚石薄膜/金属的接触界面结构直接影响到其在微电子器件领域的应用。良好的欧姆接触和较强的结合力是决定金刚石薄膜电子器件性能的关键。通过基于密度泛函理论的第一性原理方法构建了不同金属(金、钛、铜、铝、钨)/氢终端金刚石(100)基底的界面模型,研究了其结合性能。结果表明,虽然所有金属/金刚石界面均呈现稳定的界面结构,但是金、铜、铝三种金属与氢终端金刚石基底的结合能较低,金属层驰豫较小,电荷在吸附表面并没有明显转移,结合能力较差。相比之下,钨、钛与氢终端金刚石基底具有较好的结合力,结合能较高,金属层呈现明显驰豫现象,呈现较强的界面结合力。

First-principles investigation on the interface structure of different metal/hydrogen-terminated diamond (100)

The contact interface structure of the diamond film/metal directly affects its application in the field of microelectronic devices. Good ohmic contact and strong bonding force are the keys to determining the performance of diamond thin film electronic devices. The interface model of different metal (gold, titanium, copper, aluminum, and tungsten)/hydrogen-terminated diamond (100) substrates was constructed by first-principles method based on density functional theory, and the bonding properties were studied. The results show that all metal/diamond interfaces exhibit a stable interfacial structure, but the bonding energy of gold, copper, and aluminum metals to hydrogen-terminated diamond substrates is lower, the metal layer is less relaxed, the charge has no obvious transfer on the adsorption surface, and the bonding energy is weak. In contrast, tungsten, titanium have better bonding strength and higher bonding energy with hydrogen-terminated diamond surface, and the metal layer exhibits a significant relaxation phenomenon, showing a strong interface bonding force.