Here is one model
Code:
.MODEL BZX85C3V9 D IS= 5.038e-012 RS= 0.001 CJO= 1e-012 VJ= 0.75
+ TT= 5e-009 M= 0.3333 BV= 3.881 IBV= 0.02874 N= 1
+ EG= 1.11 XTI= 3 KF= 0 AF= 1 FC= 0.5
+ TNOM= 27
Diodes Inc publish spice models for many of their devices including zeners. https://www.diodes.com/design/tools/spice-models/