The SWAMI - A defect free and near-zero bird´s-beak local oxidation process and its application in VLSI technology

A new scheme for SWAMI (Side WAll Masked Isolation) process is presented which takes full advantage of LOCOS processing without suffering the difficulties. The new SWAMI technology incorporates a sloped silicon sidewall and thin nitride around the island sidewalls such that both intrinsic nitride stress and volume expansion induced stress are greatly reduced. A defect free and near-zero bird´s beak local oxidation process can be realized by the SWAMI. Fabrication technology and MOSFET electrical characteristics will be discussed. A SWAMI/CMOS circuit including 60K ROM, 2.5K SRAM, and 100 segments of display driver with 5.13 × 5.22 mm2 chip size has been successfully fabricated. The results indicate that the SWAMI is capable of replacing the LOCOS as the isolation technology for scaled VLSI circuit fabrication.