Atomically controlled processing for future Si-based devices

One of the main requirements for Si-based ultrasmall devices is atomic-order control of process technology. Here we show the concept of atomically controlled processing, based on atomic-order surface reaction control. Self-limiting formation of 1-3 atomic layers of group IV or related atoms in the thermal adsorption and reaction of hydride gases (SiH₄, GeH₄, NH₃, PH₃, CH₄ and SiH₃CH₃) on Si(100) and Ge(100) are generalized, based on the Langmuir-type model. Si epitaxial growth over the N and P layer already-formed on the Si(100) surface is achieved. It is found that a higher level of electrical P atoms exist in such films, compared with doping under thermal equilibrium conditions. These results open the way to atomically controlled technology for ultralarge-scale integrations.