Method of forming low-leakage dielectric layer

摘要

Two new processes are disclosed for forming a high quality dielectric layer. A first process includes a re-nitridation step following the oxidation of an SiN film in the formation of a dielectric layer. A second process includes a sequential nitridation step to form a SiN film in the formation of a dielectric layer. In a particular embodiment of the second process, sequential ammonia annealing at elevated temperatures is used to bake sequentially deposited thin nitride layers. By using these methods, dielectric films with higher capacitance and lower leakage current have been obtained. The methods described herein have been applied to a deep trench capacitor array, but is equally applicable for other device dielectrics including, but not limited to, stacked capacitor DRAMs.