A multi-layer extension of the semi-empirical electron transport model developed by Burke and Garth (1976) has been developed. The model has been programmed in Microsoft BASIC for the IBM personal computer and runs from 2-10 minutes for single photon energies depending on the number of layers. Model predictions for Au/Al and Al/Au/Al dose profiles agree well with the Cobalt-60 data of Wall and Burke using the best fit spectrum recently derived by Woolf and Garth using the ONETRAN code. A demonstration calculation of the relative dose profile in a 10-layer CMOS device for 200 keV x-rays is given.