Oxide passivation, substrate orientation, transistor geometry, current density, and were evaluated for their effect on the 1/f noise spectrum of monolithic transistors. For verification of previous findings correlating 1/f noise with surface-state density, C-V measurements were made at 260 Hz and 0.1 MHz. Transistors fabricated on (100)-oriented substrates with dry oxide passivation and a high ratio of emitter area to periphery provided the best 1/f noise performance. A reduction of current density and an increase in h,£ had the effect of reducing 1/f noise. The use of (100)-oriented substrates oxidized in steam and dry oxygen resulted in lower surface-state density than use of (111) substrates; these results indicate a dependence of 1/f noise on orientation. C—v curves measured at 260 Hz did not differ significantly from those measured at 0.1 MHz. © 1969 IEEE. All rights reserved.
