Abstract: A wet etching process (10) etches sacrificial oxide on a substrate without damaging a polycrystalline silicon structure on the substrate. The etching process (10) includes dipping the substrate in a surfactant (11), submerging a portion of the substrate in a recirculating bath of the etchant while injecting an inert gas into the etchant (12) to purge the etchant of oxygen, rinsing the substrate in deionized water (14), submerging a portion of the substrate in a hydrogen peroxide solution (15), rinsing the substrate for a second time (17), and drying the substrate in isopropyl alcohol vapor (18). The inert gas injected into the etchant displaces oxygen dissolved in the etchant and protects the polycrystalline silicon structure from being etched.