Thursday, December 01, 2011

US Patent 8067803 - Nanoparticle recombination sites built into DRAM memory transistor

Conventional DRAM memory cells include both a capacitor and a transistor but there has been an effort to produce DRAM cells without capacitors to decrease the cell size. This patent from Micron teaches a variation of this approach using nanoparticles as recombination sites for capacitor-less charge storage. Claim 1 reads:

1. A memory device comprising:

a partially depleted storage transistor at a surface of a substrate comprising:

a body portion located between a first source/drain region and a second source/drain region, the body portion including a heavily doped region of a second conductivity type having one of nano-particles and nano-inclusions located therein adjacent to the second source/drain region and separated from the first source/drain region, the first source/drain region and the second source/drain region comprising:

regions of a first conductivity type, and a gate structure, the gate structure wrapping at least partially around a body portion in at least two spatial planes;

a bit line connected to the first source/drain region; and

a word line connected to the gate structure.