On the Characteristics of Zinc Oxide Films Grown on (11-20) Sapphire Substrates by Atomic Layer Deposition Using Diethylzinc and Nitrous Oxide

Abstract

Zinc oxide (ZnO) films were grown on (11-20) sapphire substrates at 600 o C by atomic layer deposition (ALD) using diethylzinc (DEZn) and nitrous oxide (N 2 O). For a typical growth run, a ZnO buffer layer was deposited at low temperature (LT) prior to the growth of a bulk ZnO film. In some cases, buffer-layer annealing or post-annealing treatments were employed to optimize ZnO growth. Based on the experimental results of x-ray diffractometry (XRD) and transmission electron microscopy (TEM), all the as-grown ZnO films were found to show c-axis preferred orientation with co-existence of <1-100> ZnO <1-100> sapphire and <11-20> ZnO <1-100> sapphire relationships in the (0001)ZnO/(11-20)sapphire hetero-interface. Typical room temperature (RT) photoluminescence (PL) spectrum of the as-grownZnO film shows only near band edge (NBE) emissions without defect luminescence. ZnO films with improved quality were achieved by post-annealing or buffer-layer annealing treatments. In particular, buffer-layer annealing was found to remarkably improve the crystalline and optical properties of a ZnO film.

From Precursor Chemistry to Gas Sensors: Plasma‐Enhanced Atomic Layer Deposition Process Engineering for Zinc Oxide Layers from a Nonpyrophoric Zinc Precursor for Gas Barrier and Sensor Applications

“…[ 34 ] However, further reduction in deposition temperature was possible till date by using the extremely reactive and pyrophoric zinc alkyls namely dimethyl zinc ([ZnMe 2 ], DMZ) and diethyl zinc ([ZnEt 2 ], DEZ) among which, DEZ is by far the most commonly used precursor. [ 35 ] Owing to its high reactivity, it is the most explored Zn precursor and has been used in combination with H 2 O, [ 36 ] O 2 , [ 37 ] O 3 , [ 38 ] or N 2 O [ 39 ] as coreactants. Furthermore, DEZ was used in plasma‐enhanced (PE)ALD processes with oxygen or water plasma, especially for very low deposition temperatures down to room temperature.…”