Sunday, December 14, 2008

US Patent 7463476 - Non-catalytic CNT capacitor fabrication

Decreasing the size of memory cells has led to decreasing capacitances which are undesirable for scaling. High aspect ratio structures such as carbon nanotubes with large surface areas offer one potential solution. In the past nanotubes have been grown for such an application using a catalytic transition metal such as Fe, Co, or Ni. However, this patent from Hynix Semiconductor teaches an alternative fabrication approach that does not require a catalyst based on a "metastable polysilicon" process developed by Hynix. Claim 1 reads:

1. A method for fabricating a capacitor, comprising the steps of:

forming a conductive layer for forming a lower electrode;

forming a nanotube array including a plurality of nanotubes formed on the conductive layer without using a catalytic layer;

forming a dielectric layer on the nanotube array; and

forming an upper electrode on the dielectric layer.