Atomic‐Order Thermal Nitridation of Silicon at Low Temperatures

Abstract

Atomic‐order nitridation of Si(100) in an environment (124–1400 Pa) at 300–650°C has been investigated using an ultraclean low pressure hot‐wall reactor system. At 500°C or higher, the N atom concentration (nN) initially increases and tends to saturate to a certain value . At 400°C or lower, on the H‐terminated Si surface, the Si‐hydride decreases with increasing exposure time and becomes hardly observed when nN reaches nearly to the surface Si atom concentration . On the H‐free Si surface, nN increases up to with the appearance of the Si‐hydride instantly after exposure. It is expected that dissociatively adsorbs on the Si dangling bonds. It is found that nN is well described by Langmuir‐type physical adsorption and reaction of on the Si surface. The ultrathin nitride film shows very good characteristics as a mask against oxidation.