correct xoi and xom defaults to Angstrom and clarify comments

src/spicelib/devices/dio/diompar.c

@@ -263,11 +263,11 @@ DIOmParam(int param, IFvalue *value, GENmodel *inModel)
             model->DIOwidthPolyGiven = TRUE;
             break;
         case DIO_MOD_XOM:
-            model->DIOmetalOxideThick = value->rValue * 1e-10; /* m */
+            model->DIOmetalOxideThick = value->rValue * 1e-10; /* Angstrom -> m */
             model->DIOmetalOxideThickGiven = TRUE;
             break;
         case DIO_MOD_XOI:
-            model->DIOpolyOxideThick = value->rValue * 1e-10; /* m */
+            model->DIOpolyOxideThick = value->rValue * 1e-10; /* Angstrom -> m */
             model->DIOpolyOxideThickGiven = TRUE;
             break;
         case DIO_MOD_XM:

src/spicelib/devices/dio/diosetup.c

@@ -259,10 +259,10 @@ DIOsetup(SMPmatrix *matrix, GENmodel *inModel, CKTcircuit *ckt, int *states)
             model->DIOwidthPoly = 0.0;
         }
         if(!model->DIOmetalOxideThickGiven) {
-            model->DIOmetalOxideThick = 1e-06; /* m */
+            model->DIOmetalOxideThick = 1e4; /* 10k Angstrom */
         }
         if(!model->DIOpolyOxideThickGiven) {
-            model->DIOpolyOxideThick = 1e-06; /* m */
+            model->DIOpolyOxideThick = 1e4; /* 10k Angstrom */
         }
         if(!model->DIOmetalMaskOffsetGiven) {
             model->DIOmetalMaskOffset = 0.0;