FLOATING GATES AND METHODS OF FORMATION

摘要

The present invention generally relates to a floating gate structure and method of forming the same. The floating gate structure has an upper portion which is wider than a middle portion of the floating gate structure. The upper portion may have a flared, rounded or bulbous shape instead of being pointed or having sharp corners. The reduction in pointed or sharp features of the upper portion reduces the electric field intensity near the upper portion, which decreases current leakage through the interpoly dielectric. The method includes forming a nitride cap on the upper surface of the floating gate structure to assist in shaping the floating gate. The floating gate is then formed using multiple selective oxidation and etching processes.