Hydrogen Behavior in Top Gate Amorphous In-Ga-Zn-O Device Fabrication Process During Gate Insulator Deposition and Gate Insulator Etching

The hydrogen behavior in the amorphous In-Ga-Zn-O (a-IGZO) thin-film layer according to the device process with top gate structure was quantitatively investigated. The hydrogen quantities in the a-IGZO thin-film layer with gate insulator (w/GI) and after GI dry-etching were increased by 3.40 x 10(20) and 2.50 x 10(20)/cm(3), respectively, in comparison with without GI (w/o GI). In addition, the calculated carrier concentration of the a-IGZO thin-film layer by band alignment increased by 1.60 x 10(18) and 7.38 x 10(17)/cm(3), respectively, compared with w/o GI. Due to the plasma effect, the hydrogen quantity and the calculated carrier concentration in the a-IGZO thin-film layer after GI dry-etching slightly decreased from w/GI by 0.90 x 10(20) and 8.62 x 10(17)/cm(3), respectively. The increased hydrogen quantity in the a-IGZO thin-film layer can contribute to increase in carrier concentration by providing free electrons through the hydrogen reaction with oxygen ions or transition of hydrogen state. Here, we attempted to correlate the hydrogen effect to the increase of the carrier concentration through various physical analysis.

Automated summary

The behavior of hydrogen in the amorphous IGZO thin-film layer affects carrier concentration, with the presence or removal of gate insulator impacting hydrogen content and carrier concentration. The plasma effect helps decrease the hydrogen quantity and carrier concentration after GI dry-etching.