Characteristics on the gate insulator of metal tip field emitter arrays after wet etching process

Abstract

The effect of wet-etching process on the gate insulator for fabrication of field emitter arrays (FEAs) was examined. Three types of wet-etching process have been performed to fabricate metal tip FEAs; they are Mo (gate metal), oxide (gate insulator) and Al (release layer) etching, respectively. We examined the effect of gate insulator after wet etching through breakdown field strength and rms surface roughness. And the effect by residual ions or atoms was also examined. The breakdown field strength of gate insulator by the measurement of current voltage for immersing in oxide etchant was rapidly lowered at the expense of large etching time. However in case of Al etchant, the breakdown field strength was lowered slowly. In all cases, it has been validated through Auger electron spectroscopy (AES) analysis that the residual atom was phosphor after wet-etching process when compared cleaned with non-cleaned samples. Also, we obtained excellent result when aluminum etchant was substituted for 3% tetra-methyl ammonium hydroxide (TMAH). in case of TMAH, decrease of the breakdown field strength was the slowest, surface roughness was smoother, and it did not attack gate and tip material.