We have used a sol–gel spin-coating process to fabricate a new metal insulator–metal capacitor comprising 10-nm thick binary hafnium–zirconium–oxide (HfxZr_(1-x)O2) film on a flexible polyimide (PI) substrate. The surface morphology of this HfxZr_(1-x)O2 film was investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free film growth had occurred on the PI. After oxygen plasma pre-treatment and subsequent annealing at 250 degrees C, the film on the PI substrate exhibited a low leakage current density of 3.22 x 10^-8 A/cm2 at -10 V and maximum capacitance densities of 10.36 fF/lm2 at 10 kHz and 9.42 fF/lm2 at 1 MHz. The as-deposited sol–gel film
was oxidized when employing oxygen plasma at a relatively low temperature (~250 degrees C), thereby enhancing the electrical performance.
Meena, J. S., M.-C. Chu, J. N. Tiwari, H.-C. You, C.-H. Wu, F.-H. Ko