40 minutes to achieve a resistivity of less than approximately 30 ohms per square the regions 66 68 and 70 which are designed to enhance the conductivity of the bit line regions have a depth c of about 0 6 micrometer and a width e of approximately 5 micrometers next as represented in fig5 a two element masking layer is formed on the top surface of the substrate 50 this layer comprises for example a 5000 angstrom thick film 72 of silicon dioxide and a 900 angstrom thick film 74 of silicon nitride which serves as a junction seal in accordance with one aspect of the principles of the present invention openings are formed in the noted two element masking layer at selected spaced apart positions along each of the bit line regions thus for example as represented in fig5 an opening in the masking layer is shown above the bit line region 54 in standard ways known in the art portions of both the films 72 and 74 are removed from the depicted surface of the region 54 to form for example a rectangular opening in the masking layer the pattern of openings formed in the two element masking layer shown in fig5 is selected to correspond respectively to the particular bit pattern.