Cj. Aidinis, Dependence of the electron irradiation induced decomposition of cadmium chloride thin films on the beam energy dissipation profile, J APPL PHYS, 84(12), 1998, pp. 6667-6672
The influence of primary beam energy and film thickness on decomposition by
uniform electron irradiation of vacuum deposited thin films of cadmium chl
oride on silicon substrates has been studied for primary beam energies from
1 to 5 keV. Remaining film thickness versus dose measurements, obtained by
ellipsometry, are compared to a theoretically derived model. This model is
based on a steady state solution of the continuity equation for beam gener
ated excess carriers within the thin film with a carrier generating functio
n proportional to the Gaussian approximation for the rate of energy dissipa
tion versus depth function. The proportionality constant is equal to the en
ergy of formation of an electron-hole pair. The variation of the rate of en
ergy dissipation with depth is derived from Monte Carlo calculations. The p
rinciple of scaling is shown to apply when energy loss is normalized with r
espect to the primary beam energy and depth with respect to the Bethe range
. An energy-independent, universal thickness-versus-dose curve is proposed
in view of the application of this material as an electron beam resist. (C)
1998 American Institute of Physics. [S0021- 8979(98)06023-X].