Thursday, April 21, 2011

US Patent 7927948 - Ion implantation nanocrystal growth

It has been proposed to use nanocrystals as a replacement for floating gates to improve the scalability of non-volatile memory transistors. However, during the manufacture of nanocrystal transistors too few nanocrystals can lead to difficulty in controlling the current in the transistor channel while too many nanocrystals results in current leakage which eliminates the ability to store charge. This patent from Micron Technology teaches a solution to optimize nanocrystal density which may improve scalability on non-volatile memory transistors into the nanoscale. Claim 1 reads:

1. A method of growing nanoscale structures on a semiconductor substrate, comprising:

implanting the semiconductor substrate with ions at a selected energy and a selected dose such that a controlled distribution of nucleation sites embedded in a surface of an insulative layer is formed, the surface disposed away from an interface formed by the insulative layer disposed on the semiconductor substrate, implanted material of the ions in the surface being the nucleation sites arranged to seed growth of nanoscale structures; and

growing conductive nanoscale structures from the nucleation sites on the insulative layer by depositing material on the nucleation sites of the implanted material in the surface.