Dependence of the electrical properties of the ZnO thin films grown by atomic layer epitaxy on the reactant feed sequence

Journal Article · Sat Jul 15 04:00:00 EDT 2006 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.2209653· OSTI ID:20777303

Lee, Chongmu; Lim, Jongmin ^[1]

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1. Department of Materials Science and Engineering, Inha University, 253 Yonghyeon-dong, Incheon 402-751 (Korea, Republic of)

Nitrogen-doped, p-type ZnO films have been grown successfully on sapphire (0001) substrates by atomic layer epitaxy (ALE) using Zn(C{sub 2}H{sub 5}){sub 2} [diethylzinc (DEZn)], H{sub 2}O, and NH{sub 3} as a precursor for zinc, an oxidant, and a doping source gas, respectively. The main process parameters for the growth of p-type ZnO were the NH{sub 3} flux and the reactant feed sequence in ALE. An annealing process was performed after the ALE process. The lowest electrical resistivity of the p-type ZnO films grown by ALE was 17.9 {omega} cm with a hole concentration of 1.59x10{sup 17} cm{sup -3}. The results indicated that the carrier concentrations and carrier mobilities in the as-grown and annealed ZnO thin films depend strongly on the NH{sub 3} pulse time and on which step of an ALE cycle the NH{sub 3} doping is conducted. For both reactant feed sequences of DEZn-NH{sub 3}-H{sub 2}O and H{sub 2}O-NH{sub 3}-DEZn, n-type ZnO was changed to p-type ZnO by annealing, but the latter led to p-type ZnO with a carrier concentration after annealing higher than that in sequence 1 for the same NH{sub 3} flow rate. In addition, a model is proposed which can explain the difference between the two feed sequences in carrier concentration and carrier mobility before and after annealing. Time-dependent Hall effect measurement results also support that the nitrogen-doped ZnO film grown by ALE and then annealed at 1000 deg. C for 1 h is a p-type semiconductor.

• OSTI ID: 20777303
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films Journal Issue: 4 Vol. 24; ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMMONIA
ANNEALING
CARRIER DENSITY
CARRIER MOBILITY
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
EPITAXY
LAYERS
NITROGEN
SAPPHIRE
SEMICONDUCTOR MATERIALS
THIN FILMS
ZINC OXIDES