Contamination control and pilot manufacturing of commercial grade carbon nanotube colloidal formulations

As an intermediate between discrete molecules and bulk materials, carbon nanotubes (CNTs) require a prescribed mix of processing tactics to scalably transform them from a heterogeneous blend of metal catalysts, amorphous carbons and CNTs into a robust colloidal formulation suitable for spin-on semiconductor applications such as non-volatile memory. In this manuscript, we will show historical quality control (QC) data collected over a four year period on three sequential generations of a single formulation. Results from this data will show that using our controlled processing methods, we can reproducibly prepare liter-scale quantities of spin-on CNTs formulations, meeting quality specifications expected for other electronics-grade thin-film precursors. Presented QC data will highlight our continuous improvement efforts in trace-metal (TM) control which has ultimately allowed us to reduce our process mean from ~40 ppbw total TM to less than 3 ppbw. QC defectivity data gathered from electron and optical microscopy will also be presented on each formulation generation, along with a description of the defect taxonomy developed which has help reduce defectivity in future formulations.