A defect-free field isolation technology for high density n-channel MOS LSI´s

A unique field isolation technology has been developed for n-channel MOS LSI\´s by utilizing the HF gas reverse etching process. This new technology essentially eliminates several inherent problems of the widely used coplanar (also known as LOCOS) technology, such as process induced crystalline defects and gate oxide failure called "white ribbon". The resultant structure without the bird\´s beak, the lateral oxidation under the nitride mask, thus improved the packing density as much as 43% and 55% for 4µ and 3µ design rules, respectively.