Organic thin film transistor memories with carbon nanodots fabricated by focused ion beam chemical vapor deposition

Abstract

Metal-insulator-semiconductor field effect transistor (MISFET) structures with a nanocrystal carbon (nc-C) embedded in SiO2 thin films using a focused ion beam chemical vapor deposition (FIBCVD) system with a precursor of low energy Ga+ ion and carbon source to fabricate organic thin film transistor (OTFT) memories. The crystallinity of nc-C was investigated by Raman spectroscopy and atomic force microscopy (AFM). Raman spectra indicate the evidence of crystallization of nc-C after annealed at 600 degree celcius by the sharp peak at 1565 cm-1 in graphite (sp2), while no peak of diamond (sp3) could be seen at 1333 cm-1. The AFM images showed the nc-C dots controlled with diameter of 100 nm, 200 nm and 300 nm, respectively. The above results revealed that the nc-C dots had sufficiently stick onto SiO2 films. The characteristic of the OTFTs operated at negative gate bias shows the p-channel enhancement behavior, and shows the most saturation behavior.