p-Type ${{Cu}}_{x}{{O}}$ Thin-Film Transistors Produced by Thermal Oxidation

Abstract

Thin-films of copper oxide $({{Cu}}_{x}{{O}})$ were produced by thermal oxidation of metallic copper (Cu) at different temperatures (150–450$\ ^{\circ}{{C}}$). The films produced at temperatures of 200, 250 and 300$\ ^{\circ}{{C}}$ showed high Hall motilities of 2.2, 1.9 and 1.6 ${{cm}}^{2}\ {{V}}^{-1}{{s}}^{-1}$, respectively. Single ${{Cu}}_{2}{{O}}$ phases were obtained at 200$\ ^{\circ}{{C}}$ and its conversion to CuO starts at 250$\ ^{\circ}{{C}}$. For lower thicknesses $\sim$40 nm, the films oxidized at 250$\ ^{\circ}{{C}}$ showed a complete conversion to CuO phase. Successful thin-film transistors (TFTs) were produce by thermal oxidation of a 20 nm Cu film, obtaining p-type ${{Cu}}_{2}{{O}}$ (at 200$\ ^{\circ}{{C}}$) and CuO (at 250$\ ^{\circ}{{C}}$) with On/Off ratios of ${{6}}\times {{10}}^{1}$ and ${{1}}\times {{10}}^{2}$, respectively.

© 2013 IEEE