This paper demonstrates latchup results in a 50 Omega-cm substrate wafer in a 0.13-mum technology. Latchup evaluation will evaluate and compare a 10 Omega-cm and a 50 Omega-cm substrate wafer on the NPN bipolar current gain, betanpn, PNP bipolar current gain, betapnp,, the bipolar current gain product, betapnpbetanpn, undershoot, and overshoot phenomena.