@User there is a model for the

nfet_20v0_zvt

transistor, but it is not included from the toplevel

sky130.lib.spice

file. This suggest that it is either disabled or not reliable. May be @User has more precise info on this. For the

tt

process corner (as well as all other corners), as you see there is no

nfet_20v0*

inclusion in the top model file and not even in the included sub-files. I can try to manually include the

sky130_fd_pr__nfet_20v0_zvt__subcircuit.pm3.spice

and see what happens.

.lib tt
* MOSFET
.include "../cells/nfet_01v8/sky130_fd_pr__nfet_01v8__tt.corner.spice"
.include "../cells/nfet_01v8_lvt/sky130_fd_pr__nfet_01v8_lvt__tt.corner.spice"
.include "../cells/pfet_01v8/sky130_fd_pr__pfet_01v8__tt.corner.spice"
.include "../cells/nfet_03v3_nvt/sky130_fd_pr__nfet_03v3_nvt__tt.corner.spice"
.include "../cells/nfet_05v0_nvt/sky130_fd_pr__nfet_05v0_nvt__tt.corner.spice"
.include "../cells/esd_nfet_01v8/sky130_fd_pr__esd_nfet_01v8__tt.corner.spice"
.include "../cells/pfet_01v8_lvt/sky130_fd_pr__pfet_01v8_lvt__tt.corner.spice"
.include "../cells/pfet_01v8_hvt/sky130_fd_pr__pfet_01v8_hvt__tt.corner.spice"
.include "../cells/esd_pfet_g5v0d10v5/sky130_fd_pr__esd_pfet_g5v0d10v5__tt.corner.spice"
.include "../cells/pfet_g5v0d10v5/sky130_fd_pr__pfet_g5v0d10v5__tt.corner.spice"
.include "../cells/pfet_g5v0d16v0/sky130_fd_pr__pfet_g5v0d16v0__tt.corner.spice"
.include "../cells/nfet_g5v0d10v5/sky130_fd_pr__nfet_g5v0d10v5__tt.corner.spice"
.include "../cells/nfet_g5v0d16v0/sky130_fd_pr__nfet_g5v0d16v0__tt_discrete.corner.spice"
.include "../cells/esd_nfet_g5v0d10v5/sky130_fd_pr__esd_nfet_g5v0d10v5__tt.corner.spice"
.include "corners/tt/nonfet.spice"
* Mismatch parameters
.include "../cells/nfet_01v8/sky130_fd_pr__nfet_01v8__mismatch.corner.spice"
.include "../cells/pfet_01v8/sky130_fd_pr__pfet_01v8__mismatch.corner.spice"
.include "../cells/nfet_01v8_lvt/sky130_fd_pr__nfet_01v8_lvt__mismatch.corner.spice"
.include "../cells/pfet_01v8_lvt/sky130_fd_pr__pfet_01v8_lvt__mismatch.corner.spice"
.include "../cells/pfet_01v8_hvt/sky130_fd_pr__pfet_01v8_hvt__mismatch.corner.spice"
.include "../cells/nfet_g5v0d10v5/sky130_fd_pr__nfet_g5v0d10v5__mismatch.corner.spice"
.include "../cells/pfet_g5v0d10v5/sky130_fd_pr__pfet_g5v0d10v5__mismatch.corner.spice"
.include "../cells/nfet_05v0_nvt/sky130_fd_pr__nfet_05v0_nvt__mismatch.corner.spice"
.include "../cells/nfet_03v3_nvt/sky130_fd_pr__nfet_03v3_nvt__mismatch.corner.spice"
* Resistor/Capacitor
.include "r+c/res_typical__cap_typical.spice"
.include "r+c/res_typical__cap_typical__lin.spice"
* Special cells
.include "corners/tt/specialized_cells.spice"
* All models
.include "all.spice"
* Corner
.include "corners/tt/rf.spice"
.endl