A Two‐Step Oxidation Process to Improve the Electrical Breakdown Properties of Thin Oxides

We have developed a technique for growth of thin oxides (80–90Å) with an intermediate annealing step. The oxides exhibit a tight distribution in breakdown voltage measurements leading to defect density less than 5/cm 2 , intrinsic breakdown field of 12 MV/cm, and a value of less than 1 × 10 10 / cm 2 ‐ eV for interface trap density in midgap. The inferior electrical properties of thin oxides grown by conventional methods in dry oxygen with Ar dilution have been correlated with Si ‐ SiO 2 interface roughness using high resolution transmission electron microscopy. The intermediate annealing process may be used to improve the endurance and retention properties of EEPROM devices and alleviate the degradation of thin oxides in short‐channel MOS devices.