HIGH-PERFORMANCE SUPERTHIN OXIDE/NITRIDE/OXIDE STACKED DIELECTRICS FORMED BY LOW-PRESSURE OXIDATION OF ULTRATHIN NITRIDE

Abstract

High-performance superthin oxide/nitride/oxide (O/N/O) stacked dielectrics have been successfully achieved by oxidizing ultrathin nitride films in low-pressure dry oxygen at 850 degrees C for 30 min. The low leakage current and the high reliability of this O/N/O structure are attributed to the growth of the top oxide on the nitride, which is confirmed by Auger electron spectroscopy (AES) depth profiles and step-by-step diluted-HF etching results. The commonly used Net oxidation of the nitrides at atmospheric pressure cannot attain an effective oxide thickness of as low as 46 Angstrom. Furthermore, the dry oxidation of nitrides at atmospheric pressure can only yield a nitride/oxide (N/O) structure, which results in high leakage current. Therefore: our novel technique is promising for future dynamic-random-access-memory (DRAM) technology.