Diffusion from polymer spin-on films: Measurements and simulations

Abstract

The possibilities of diffusion from polymer spin-on films have been investigated for the purpose of obtaining shallow junctions in Si, GaAs, InP, and InGaAs. Compared to the conventional diffusion techniques, diffusion from polymer spin-on films is simpler and more controllable. The peculiarities of the method are associated with a uniform distribution of the dopant atoms in the three-dimensional network of the polymer chains. The possibilities have been demonstrated for control of the atomic concentration of B in silicon and of Zn in III–V compounds (from 1021 to 1017 cm−3) and for obtaining shallow p-n junctions; for example, a junction depth of 40 nm has been obtained in silicon. Diffusion conditions have been analyzed which provide a near-entire activation of the impurity. Moreover, gettering the defects and the background impurities by the spin-on film in the near-surface region of the semiconductor has been investigated.