Growth of a stacked silicon nitride/silicon oxide dielectric on Si (100)

We have recently developed processes to grow ultrathin amorphous silicon oxide and amorphous silicon nitride layers on clean Si (111) and Si (100) surfaces exploring the self-limiting nature of the direct oxidation of Si with O₂, and the self-limiting nature of the direct nitridation of Si with atomic N produced by microwave dissociation of N₂, at processing temperatures around 500 °C. In some of today’s microprocessor devices mixed dielectric systems are used as complementary metal oxide semiconductor gate dielectrics. We demonstrate the use of our processes to produce such systems in various structures, and with maximum control, by exposing oxide to N, or nitride to O₂ at 500 °C. In addition we produce a stacked layer, consisting of 7–8 Å of SiO₂ on top of Si (100), with a layer of varying thickness of Si₃N₄ grown on top of this structure. The growth of Si₃N₄ occurs at room temperature in this process. Such structures or thermally postprocessed structures thereof should be further examined as potential stacked gate dielectrics in the next generation of Si-based microelectronics.