Observation of Self-limiting Regime in the Atomic Layer Deposition of ZnO Films using Nitrous Oxide as the Oxygen Supply

We report the observation of self-limiting process in the atomic layer deposition (ALD) of zinc oxide (ZnO) films on (0001) sapphire substrates at low temperatures using diethylzinc (DeZn) and nitrous oxide (N2O). I was found that a monolayer-by- monolayer growth regime occurred in a range of DeZn flow rates from 5.7 to 8.7 μmole/min. Furthermore, the temperature window for the self-limiting process of the ALD-grown ZnO films was also observed ranging from 290 to 310 °. The transmission and absorption spectra of the ZnO films prepared in the self-limiting regime show good optical characteristics with tramsmittance being more than 80% in the visible light region. Experimental results indicate that ZnO films grown in the self-limitng regime all exhibit improved materials characteristics and thickness uniformity.