CAP LAYER FOR METAL CONTACTS OF A SEMICONDUCTOR DEVICE

文件类型：PDF文档
文件大小：3121K
Techniques are disclosed for forming transistors including a conductive cap layer formed on metal contacts to help protect the metal contacts from undesired oxidation. The cap layer includes an oxygen barrier layer that includes chromium (Cr) and/or iridium (Ir) to protect the underlying metal contacts (e.g., source/drain contacts) from being exposed to oxygen in the environment during subsequent processing after the metal contacts have been formed. Thus, the cap layer enables the use of hygroscopic and/or highly reactive metals in the metal contacts, such as rare earth metals (e.g., ytterbium, erbium, and yttrium). In some cases, the cap layer includes a diffusion barrier layer between the oxygen barrier layer and a corresponding metal contact to help prevent undesired intermixing of the materials included in the two features. For example, if the oxygen barrier layer includes iridium, a diffusion barrier layer may be employed to prevent undesired intermetallics from forming.