Pyramidal Structure Formation at the Interface between III/V Semiconductors and Silicon

An enhancement of computer performance following Moore’s law requires the miniaturization of semiconductor devices. Presently, their dimensions reach the nanoscale. Interfaces between materials become increasingly important as the volume is reduced. It is shown here how a pyramidal interface structure is formed irrespective of the conditions applied during the growth of two semiconductors. This drastically changes the common view of interfaces, which were assumed to be either atomically abrupt or interdiffused. Especially in semiconductor heteroepitaxy, a simple surface segregation of one atomic species is often assumed. It is proven by first-principles computations and kinetic modeling that the atom mobility during growth and the chemical environment at the interface are the decisive factors in the formation of the actual structure. Gallium phosphide grown on silicon was chosen as representative, nearly unstrained material combination to study the fundamental parameters influencing the interface morphology. Beyond that, this system has significant impact for cutting-edge electronic and optoelectronic devices. The findings derived in this study can be generalized to aid the understanding of further relevant semiconductor interfaces. This knowledge is crucial to comprehend current and steer future properties of miniaturized devices.