Good High-Temperature Stability of $\hbox{TiN}/ \hbox{Al}_{2}\hbox{O}_{3}/\hbox{WN}/\hbox{TiN}$ Capacitors

For the first time, good thermal stability up to an annealing temperature of 1000degC has been demonstrated for a new TiN/Al
₂
O
₃
/WN/TiN capacitor structure. Good electrical performance has been achieved for the proposed layer structure, including a high dielectric constant of ~ 10, low leakage current of 1.2times10
^-7
A/cm
²
at 1 V, and excellent reliability. A thin WN layer was incorporated into the metal-insulator-metal capacitor between the bottom TiN electrode and the Al
₂
O
₃
dielectric suppressing of interfacial-layer formation at Al
₂
O
₃
/TiN interfaces and resulting in a smoother Al
₂
O
₃
/TiN interface. This new layer structure is very attractive for deep-trench capacitor applications in DRAM technologies beyond 50 nm.