Effects of deposition and annealing conditions on the defects in the Al/glass composites of TFT specimens

摘要

Al/glass specimens are prepared following the orthogonal table of five-level six-factorial (L_(25)(5~6)) design. The governing factors for the preparation of the specimens are deposition conditions, annealing temperature and annealing time. Defects, including hillocks and nanovoids, are found to be created during the annealing process. The threshold value of the annealing stress (σ_(an)) required for the incipience of hillocks is thus determined. The stress change parameter, σ_f-σ_(an) (σ_f :internal stress after annealing), is a positive value that increases linearly with σ_(an). The density of hillocks increases linearly with (σ_f-σ_(an)) when the value of the stress change parameter is beyond the critical value (130 MPa). Nanovoids are produced even in specimens without hillocks. The wedge angle that forms in a specimen after wet etching linearly decreases with decreasing (σ_f-σ_(an)). A high wedge angle lowers the hillock density at the wedge slope. The electrical resistance of the gate layer linearly increases with increasing product value (R~*) of the mean size (area) and the density of nanovoids. R~* increases nonlinearly with increasing (σ_f-σ_(an)).