Abstract: A method of controlling implantation dosages during coding of read-only memory (ROM) devices is disclosed. According to the method, a semi-manufactured ROM device having a plurality of gates with identically designed gate widths is formed, followed by the formation of a first photoresist layer over the semi-manufactured ROM device. The first photoresist layer is selectively exposed to develop a pattern of pre-code openings, with each pre-code opening being positioned over a word line and between two adjacent bit lines intersecting the word line and with the pre-code openings having substantially identical sizes. A second photoresist layer is then formed over the first photoresist layer, followed by selectively exposing the second photoresist layer to develop a pattern of real-code openings therein, with the real-code openings having substantially identical sizes. A tuned dosage of ions is then implanted through intersections of the real-code and pre-code openings to thereby code the ROM device.

Abstract: An air return bulkhead having a filter for filtering dust, dirt and debris out of an airflow prior to its entry into an evaporator or heat exchanger. The apparatus is particularly designed for use within a climate-controlled space such as a trailer or truck interior. Air pulled into the refrigeration system first enters the air return bulkhead where particles and debris are filtered. The air then travels through the refrigeration system and back into the climate-controlled space.