PELOX integrated PBL

Polysilicon buffered LOCOS (PBL) does not exhibit sufficient field oxide recess to support aggressive device scaling without the introduction of processes which are difficult to control. Recently, polysilicon encapsulated local oxidation (PELOX) has been proposed as an easily scaled isolation technique that exhibits LOCOS equivalent recess. The integration of PELOX into an existing PBL 1-Mb DRAM baseline process is described. PELOX-integrated PBL (PIPBL) is demonstrated to enhance final field oxide recess without increasing encroachment. The improved final field oxide recess is shown to provide increased process margin as evidenced by superior probe yield