Patent ID: 8536011

Claim:
A memory device comprising: a substrate; a source region formed in the substrate, the source region comprising phosphorus and arsenic, the phosphorus in the source region being formed to a greater depth below an upper surface of the substrate than the arsenic in the source region, a deepest portion of the source region including the phosphorus, an upper portion of the source region including a combination of the phosphorus and the arsenic, and the deepest portion of the source region having a smaller width than the upper portion of the source region; a drain region formed in the substrate, the drain region comprising phosphorus and arsenic, the phosphorus in the drain region being formed to the greater depth below the upper surface of the substrate than the arsenic in the drain region, a deepest portion of the drain region including only the phosphorus, an upper portion of the drain region including a combination of the phosphorus and the arsenic, and the deepest portion of the drain region having a smaller width than the upper portion of the drain region; a first isolation region located adjacent to the deepest portion of the source region, and the deepest portion of the source region preventing leakage currents from being generated at a first junction, the first junction being associated with the source region and located near the first isolation region, and a top surface of the first isolation region being approximately even with the upper surface of the substrate; a first silicide layer formed over the source region, the first silicide layer wrapping around and extending to a greater depth, into the source region, in an area adjacent to the first isolation region than in other areas of the source region, the first silicide layer extending into the source region without reaching the first junction, and a lower portion of the first silicide layer being adjacent to the first isolation region; a second isolation region located adjacent to the deepest portion of the drain region, the deepest portion of the drain region preventing leakage currents from being generated at a second junction near the second isolation region; and a second silicide layer formed over the drain region, the second silicide layer wrapping around and extending to a greater depth, into the drain region, in an area adjacent to the second isolation region than in other areas of the drain region.