We investigate the basic properties of focused electron beam (FEB)-damaged Josephson junctions on silicon (Si) substrates for high-frequency device applications. YBa2Cu3O7-y (YBCO) Josephson junction arrays were also fabricated by FEB irradiation to confirm the junction uniformity and to investigate their applicability. The junctions exhibit resistively shunted junction (RSJ)-like current-voltage (I-V) curves and the microwave-induced Shapiro steps for all operation temperatures. Two-junction arrays show single-junction-like behavior with the Shapiro steps in an array up to 2 mV. Microwave-induced Shapiro steps correspond to the double voltages Vn=2nVJ, where VJ=f0h/2e in two-junction arrays. The microwave power dependence of I-V curves shows the steps corresponding to the RSJ model.

A Monte Carlo method for the passage of electrons based on a single scattering model is developed. A code based on this method is operable on personal computers, and has been applied to analyze electron behavior in a layered system consisting of Ti (an accelerator window), air, cellulose triacetate (CTA) and backing material irradiated by 300 keV electrons. The energy spectra and the angular distributions of electrons on the CTA surface as well as depth distributions of energy deposition in the CTA for various backing materials have been obtained. Some of these results are compared with experiments, and show fairly good agreement.