The present invention pertains to implementing a dual poly process in forming
a transistor based memory device. The process allows buried bitlines to be formed
with less energy and to shallower depths than conventional bitlines to save resources
and space, and to improve Vt roll-off. Oxide materials are also formed over the
buried bitlines to improve (e.g., increase) a breakdown voltage between the bitlines
and wordlines, thus allowing for greater discrimination between programming and
erasing charges and more reliable resulting data storage. The process also facilitates
a reduction in buried bitline width and thus allows bitlines to be formed closer
together. As a result, more devices can be "packed" within the same or a smaller area.