Experimental study of interface traps in MOS capacitor with Al-doped HfO2

Interface trap density (Dit) in a metal oxide semiconductor (MOS) capacitor with an aluminum-doped hafnium oxide (Al:HfO2) layer is investigated using the conductance method. Three device-under-tests (DUTs) were fabricated to investigate the impact of Al concentration in HfO2 on Dit. Note that the atomic layer deposition cycle ratio of HfO2:Al2O3 for DUT A, B, and C was varied from 3:1, 5:1, and 10:1, respectively. It was observed that the extracted Dit of DUT C is 3.84 × 1013 cm−2 eV−1 (which is the lowest value in the three DUTs). In addition, the measured leakage current of DUT C is the lowest. The optimum Al concentration in Al:HfO2 would pave a new road for future CMOS technology.