Ballistic-electron emission microscopy (BEEM), performed under ultrahigh vacuum conditions at the room-temperature-grown Au/n-Si(111)7X7 interface, allows a measurement of the BEEM current for tip biases up to almost-equal-to 8 V without a noticeable change in ballistic transmissivity. The differences of the present results to previous reports, where either no BEEM current was observed or the transmissivity was modified when applying high tip voltages, can be explained by the absence of intermixing at the Au/Si interface. Scanning tunneling microscope images of almost-equal-to 40-angstrom-thick Au films reveal a characteristic topography of the metal surface with almost-equal-to 2.5 angstrom high circular terraces stacked in up to four stages.