is it because of w and l scale? because for 01v8 device scales of w and l is there in 01v8__tt.corner.spice but g5v0d10v5 device in g5v0d10v5__tt.corner.spice scale set is not given

all transistors have a 1e-6 scaling. The g5v0d10v5 transistor has minimum L=0.5 (that evaluates to 0.5e-6 m) . It is advisable to set : .options wnflag=1 in your simulation file to force correct model selection based on W and number of fingers (nf). also create a .spiceinit file in your home directory or in the directory where simulator is run, with the following content: set ngbehavior=hs