Spatial variation of TSV capacitance and method of stabilization with Al2O3-induced negative fixed charge at the silicon-liner interface

Stable TSV capacitance is desired to control spatial TSV performance variation due to non-uniform hot-spot heating. Thin Al
₂
O
₃
is inserted between PETEOS liner and Si substrate to induce negative fixed charge (Q
_f
= -7.44 × 10
¹¹
cm
^-2
). This causes flat-band voltage shift (ΔV
_FB
= +7.37 V) and the TSV is operated in the stable accumulation region within the operating voltage of interest (0-5 V). The leakage current density of this combination is reduced by 10 X with annealing in forming gas at 300°C.