A manufacturing method for a dual bit flash memory includes providing a semiconductor substrate and depositing a charge-trapping dielectric layer with the depositing performed without using ammonia at an ultra-slow deposition rate. First and second bitlines are implanted and a wordline layer is deposited. A hard mask layer is deposited over the wordline layer. A photoresist is deposited over the wordline layer and used to form a hard mask. The photoresist is removed. The wordline layer is processed using the hard mask to form a wordline and the hard mask is removed. A reduced hydrogen, high-density data retention liner to reduce charge loss, covers the wordline and the charge-trapping dielectric layer. An interlayer dielectric layer is deposited over the data retention liner.