Evans D A, Roberts O R, Williams G T, Vearey-Roberts A R, Bain F, Evans S, Langstaff D P, Twitchen D J
Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth SY23 3BZ, UK.
J Phys Condens Matter. 2009 Sep 9;21(36):364223. doi: 10.1088/0953-8984/21/36/364223. Epub 2009 Aug 19.
A review of diamond-metal contacts is presented with reference to reported values of interfacial potential (Schottky) barriers and their dependence on macroscopic and microscopic properties of the diamond surface, the interface and the metal. No simple model can account for the overall spread of p-diamond barriers, although there are, for certain metals, correlations with metal electronegativity, interface chemistry and diamond surface preparation. Detailed studies are presented for a selected contact (Al-p-diamond) using real-time monitoring during metal growth from sub-nanometre to bulk films and subsequent in situ heating to 1000 °C. This contact, prepared in a clean vacuum environment on characterized single-crystal substrates, provides a case study for a combined in situ electrical and spectroscopic investigation using IV measurements for macroscopic diodes and real-time photoelectron spectroscopy for nanoscale metal films. Band bending during growth leads to a rectifying contact with a measured IV barrier height of 1.05 V and an ideality factor of 1.4. A transition from layered to clustered growth of the metal film is revealed in the real-time measurements and this is confirmed by AFM. For the annealed contact, a direct correlation is revealed by real-time photoemission between the onset of interfacial carbide formation and the change from a rectifying to an ohmic contact at 482 °C.
本文综述了金刚石与金属的接触，参考了已报道的界面势（肖特基）势垒值及其对金刚石表面、界面和金属的宏观及微观性质的依赖性。尽管对于某些金属而言，p型金刚石势垒的整体分布与金属电负性、界面化学和金刚石表面制备存在相关性，但尚无简单模型能够解释其全部情况。本文针对选定的接触（铝-p型金刚石）进行了详细研究，在金属从亚纳米薄膜生长至体相薄膜的过程中进行实时监测，并随后进行原位加热至1000°C。这种在清洁真空环境中制备在经过表征的单晶衬底上的接触，为使用宏观二极管的IV测量和纳米级金属薄膜的实时光电子能谱进行联合原位电学和光谱研究提供了一个案例。生长过程中的能带弯曲导致形成具有1.05 V的测量IV势垒高度和1.4的理想因子的整流接触。实时测量揭示了金属薄膜从分层生长到簇状生长的转变，这一点通过原子力显微镜得到了证实。对于退火后的接触，实时光发射揭示了在482°C时界面碳化物形成的起始与从整流接触转变为欧姆接触之间的直接相关性。
