Effect of off-axis implant on the characteristics of advanced self-aligned bipolar transistors

This letter discusses the effect of off-axis implant on the characteristics of advanced self-aligned bipolar transistors utilizing a sidewall-spacer technology. Experimental results are presented to show that as a result of offsetting the base profile with respect to the emitter profile due to the sidewall shadowing effect, the 7° off-axis implant causes orientation-dependent perimeter punchthrough at one of the emitter edges and orientation-dependent perimeter tunneling at the other emitter edge.