Poly Encapsulated LOCOS Lateral Isolation for 0.25 μm CMOS

In this paper the feasibility of a lateral isolation scheme based on poly encapsulated LOCOS for 0.25 μm CMOS technologies is demonstrated. Excellent bird´s beak dimension control is achieved with limited process complexity. The influence of field oxide recess and presence of a cavity on bird´s beak dimensions is investigated. Oxide thinning effects are studied. Finally, good gate oxide integrity and narrow-channel behaviour results on 0.25 μm CMOS lots are shown.