Have noticed something odd in the sky130 models I'm using (version cd1748bb197f9b7af62a54507de6624e30363943): there are what I believe are breakdown voltages for diodes in a lot of the spice models, but they seem to be misnamed 'vb' rather than 'bv'

+ vb = 11.7 ; Units: volt

+ ibv = 0.00106 ; Units: amper

If I change this to 'bv' as ngspice likes, to match the ibv, then I get nice sims, as attached. This is true of both sky130_fd_pr__diode* type things and *__parasitic__diode type things.

Great catch! Could you open an issue here so it doesn't get lost: https://github.com/efabless/skywater-pdk-libs-sky130_fd_pr/issues

Wil do