Operating TSV in Stable Accumulation Capacitance Region by Utilizing $\hbox{Al}_{2}\hbox{O}_{3}$-Induced Negative Fixed Charge

The variation of through-silicon-via (TSV) capacitance caused by nonuniform hot-spot heating can lead to spatial circuit performance variation; this effect is undesirable for 3-D IC design. Hence, stable TSV capacitance is desired to overcome this issue. In this letter, stable TSV capacitance is achieved by utilizing Al
₂
O
₃
-induced negative fixed charge (|Q
_f
| = 7.44 × 10
¹¹
cm
^-2
) at the Si-liner interface. This causes a positive shift in the flat-band voltage (ΔV
_FB
= 6.85 V) and results in the TSV operating in the stable accumulation capacitance region within operating voltage of interests (~0-5 V). The leakage current density of the TSV with Al
₂
O
₃
layer and PETEOS liner is improved by ~10× after annealing in forming gas (N
₂
/H
₂
) at 300 °C for 30 min.