A reduction in parasitic leakages of shallow trench isolation vias is disclosed wherein the distance between the silicon nitride liner and the active silicon sidewalls is increased by depositing an insulating oxide layer prior to deposition of the silicon nitride liner. Preferably, the insulating oxide layer comprises tetraethylorthosilicate. The method comprises of etching one or more shallow trench isolations into a semiconductor wafer; depositing an insulating oxide layer into the trench; growing a thermal oxide in the trench; and depositing a silicon nitride liner in the trench. The thermal oxide may be grown prior to or after deposition of the insulating oxide layer.