Monolithic 3D DRAM

3d ic

Technology

Monolithic 3D IC technology can be applied to producing a monolithically stacked single crystal silicon double-gated floating body DRAM memory. Lithography steps are shared among multiple memory layers to reduce bit cost. Peripheral circuits below the monolithic memory stack provide control functions.

Reduce DRAM bit cost without investing in expensive scaling down.

Benefits

  • 3.3X the density of conventional stacked capacitor DRAM
  • Same number of litho steps as conventional stacked cap DRAM
  • Single crystal silicon on all layers
  • Scalable: Multiple generations of cost-per-bit improvement for same equipment cost and process node: use the same fab for 3 generations
  • Forestalls next gen litho-tool risk
  • Avoids the  red bricks and costs of capacitor scaling & new cell transistor development


Process Flow

Our 3D DRAM technology innovatively combines these well-studied technologies:
  • Monolithic 3D with litho steps shared among multiple memory layers
  • Stacked Single crystal Si with ion-cut
  • Double gate floating body RAM  cell with charge stored in body

3d ic

For more details, please see

[1] "Monolithic 3D DRAM Technology", MonolithIC 3D Inc.'s Invited Presentation at the American Vacuum Society Workshop on 3D Packaging, June 2011.
[2] Our blog-post in June 2011.
[3] Our blog-post on cost of ion-cut, July 2011.