devices/mos*: prevent NaN in sqrt for negative value of model parameter `PHI'

src/spicelib/devices/mos1/mos1temp.c

@@ -52,6 +52,12 @@ MOS1temp(GENmodel *inModel, CKTcircuit *ckt)
 
     /* now model parameter preprocessing */
 
+        if (model->MOS1phi <= 0.0) {
+            SPfrontEnd->IFerror (ERR_FATAL,
+               "%s: Phi is not positive.", &model->MOS1modName);
+            return(E_BADPARM);
+        }
+
         if(!model->MOS1oxideThicknessGiven || model->MOS1oxideThickness == 0) {
             model->MOS1oxideCapFactor = 0;
         } else {

src/spicelib/devices/mos2/mos2temp.c

@@ -53,6 +53,11 @@ MOS2temp(GENmodel *inModel, CKTcircuit *ckt)
         arg1 = -egfet1/(kt1+kt1)+1.1150877/(CONSTboltz*(REFTEMP+REFTEMP));
         pbfact1 = -2*vtnom *(1.5*log(fact1)+CHARGE*arg1);
 
+        if (model->MOS2phi <= 0.0) {
+            SPfrontEnd->IFerror (ERR_FATAL,
+               "%s: Phi is not positive.", &model->MOS2modName);
+            return(E_BADPARM);
+        }
 
         if(!model->MOS2oxideThicknessGiven) {
             model->MOS2oxideThickness = 1e-7;

src/spicelib/devices/mos3/mos3temp.c

@@ -53,6 +53,12 @@ MOS3temp(GENmodel *inModel, CKTcircuit *ckt)
                                                  CONSTKoverQ);
         ni_temp=1.45e16*nifact;
 
+        if (model->MOS3phi <= 0.0) {
+            SPfrontEnd->IFerror (ERR_FATAL,
+               "%s: Phi is not positive.", &model->MOS3modName);
+            return(E_BADPARM);
+        }
+
         model->MOS3oxideCapFactor = 3.9 * 8.854214871e-12/
                 model->MOS3oxideThickness;
         if(!model->MOS3surfaceMobilityGiven) model->MOS3surfaceMobility=600;

src/spicelib/devices/mos6/mos6temp.c

@@ -51,6 +51,12 @@ MOS6temp(GENmodel *inModel, CKTcircuit *ckt)
 
     /* now model parameter preprocessing */
 
+        if (model->MOS6phi <= 0.0) {
+            SPfrontEnd->IFerror (ERR_FATAL,
+               "%s: Phi is not positive.", &model->MOS6modName);
+            return(E_BADPARM);
+        }
+
         if(!model->MOS6oxideThicknessGiven || model->MOS6oxideThickness == 0) {
             model->MOS6oxideCapFactor = 0;
         } else {

src/spicelib/devices/mos9/mos9temp.c

@@ -54,6 +54,11 @@ MOS9temp(GENmodel *inModel, CKTcircuit *ckt)
                                                                   CONSTKoverQ);
         ni_temp=1.45e16*nifact;
 
+        if (model->MOS9phi <= 0.0) {
+            SPfrontEnd->IFerror (ERR_FATAL,
+               "%s: Phi is not positive.", &model->MOS9modName);
+            return(E_BADPARM);
+        }
 
         model->MOS9oxideCapFactor = 3.9 * 8.854214871e-12/
                 model->MOS9oxideThickness;