Surface segregation of arsenic and phosphorus from buried layers during Si molecular beam epitaxy

Abstract

Articles you may be interested inFabrication of laterally selected Si doped layer in GaAs using a low-energy focused ion beam/molecular beam epitaxy combined system Unintentional doping of silicon films grown on heavily doped buried layers of arsenic and phosphorus during silicon molecular beam epitaxy has been studied by spreading resistance profiling and x-ray photoelectron spectroscopy. The measurements indicate that dopant surface segregation during growth is responsible for the unintentional doping. The segregation phenomenon has been characterized over a growth temperature range of 450-750°C. The growth on heavily doped buried layers has implications for device applications such as Si/SiGe heterojunction bipolar transistors. Epitaxial processes to circumvent this effect and create abrupt doping profiles are explored.

Determination of the surface segregation ratio of P in Si(1 0 0) during solid-source molecular beam epitaxial growth

“…However, for P to be used as an n-dopant in an epitaxial process, there must be precise knowledge of the physical stability of P during the growth process. It has been shown that Sb, As and P segregate towards the surface during growth, and that the segregation is a function of growth temperature [9][10][11][12][13]. An illustration of the segregation of P is demonstrated in figure 1.…”

(Invited) Si-Ge-Sn Technologies: From Molecules to Materials to Prototype Devices

“…In recent device applications, this precursor method has proven to be far superior to current state-of-the-art approaches for n-type doping utilizing arsine and phosphine which tend to significantly reduce the growth rates due to complicated surface reactions at the growth front (26)(27)(28). The use of the latter compounds containing relatively strong P-H and As-H bonds are also known to require high temperature depositions, which leads to clustering, precipitation and surface segregation of the dopants, thereby inhibiting the formation of compositionally uniform profiles and thus degrading the overall quality of the material (29). Ultimately, these source-and processrelated issues severely limit the active carrier concentrations achievable to levels below the 10 19 atoms/cm 3 range (30).…”

Ultra-low-temperature homoepitaxial growth of Sb-doped silicon

“…The creation of sharp n-type dopant profiles in silicon during growth is challenging due to the high surface segregation ratio of the common ntype dopants Sb, P, and As [5,6]. Of these dopants, Sb is the most commonly used and has a lower surface segregation than P and As.…”