The impact on in-situ-hydrogen-plasma treatment for zinc oxide plasma enhanced atomic layer deposition

Abstract ZnO films were deposited by the PEALD using oxygen and hydrogen plasmas at 100 °C. As the oxygen plasma increased by 200 W, the growth rate saturated to 1.78 A/cycle over 150 W. The film resistivity increased to 4.95 × 10 3 Ω cm without a significant change of film crystallinity but the carrier concentration drastically decreased to 4.87 × 10 13  cm −3 as the oxygen plasma power increased to 200 W. Interestingly, as the hydrogen plasma power increased during ZnO PEALD (DEZ + O 2 plasma + H 2 plasma), the growth rate, film crystallinity and resistivity drastically decreased. Although the crystallinity of z -axis ZnO film decreased, the ZnO film exhibited the conducting property. Based on x-ray photoelectron spectroscopy and auger electron spectroscopy analysis, the higher oxygen plasma power may help to decrease oxygen vacancies but the higher hydrogen plasma power can induce in generation oxygen vacancies and hydroxyl groups in ZnO films, strongly relating with the changes of carrier concentrations. The hydrogen and oxygen plasma exhibited conflicting behaviors in terms of ZnO electrical property. Thus, the electrical properties on ZnO film PEALD are easily manipulated even on very low deposition temperature, with only selecting oxygen and hydrogen plasma conditions.

[1]  S. Ogale,et al.  On the origin of high-temperature ferromagnetism in the low-temperature-processed Mn–Zn–O system , 2004, Nature materials.

[2]  J. Son,et al.  Horizontal ZnO Nanowires for Gas Sensor Application: Al-Doping Effect on Sensitivity , 2009 .

[3]  Jianguo Lu,et al.  Structural, optical, and electrical properties of (Zn,Al)O films over a wide range of compositions , 2006 .

[4]  D. Wood,et al.  Transparent conducting zinc oxide thin films doped with aluminum and molybdenum , 2007 .

[5]  Hyungjun Kim,et al.  Characteristics and applications of plasma enhanced-atomic layer deposition , 2011 .

[6]  Won-Jae Lee,et al.  The role of oxygen vacancies in epitaxial-deposited ZnO thin films , 2007 .

[7]  John B. Goodenough,et al.  X-ray photoemission spectroscopy studies of Sn-doped indium-oxide films , 1977 .

[8]  E. Fortunato,et al.  Fully Transparent ZnO Thin‐Film Transistor Produced at Room Temperature , 2005 .

[9]  R. Hummel.  Electronic properties of materials , 1985 .

[10]  Sbs Stephan Heil,et al.  In situ spectroscopic ellipsometry as a versatile tool for studying atomic layer deposition , 2009 .

[11]  W. Gebhardt,et al.  MOCVD layer growth of ZnO using DMZn and tertiary butanol , 1998 .

[12]  H. Morkoç,et al.  A COMPREHENSIVE REVIEW OF ZNO MATERIALS AND DEVICES , 2005 .

[13]  H. Ohno,et al.  Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO , 2004 .

[14]  Hyun Jae Kim,et al.  Effects of UV light and carbon nanotube dopant on solution-based indium gallium zinc oxide thin-film transistors , 2011 .

[15]  Shinzo Takata,et al.  Highly Conductive and Transparent Aluminum Doped Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering , 1984 .

[16]  E. Fortunato,et al.  Highly Sensitive ZnO Ozone Detectors at Room Temperature , 2003 .

[17]  Masashi Kawasaki,et al.  Room-temperature ultraviolet laser emission from self-assembled ZnO microcrystallite thin films , 1998 .

[18]  Shui-Tong Lee,et al.  Aluminum-doped zinc oxide films as transparent conductive electrode for organic light-emitting devices , 2003 .

[19]  J. Skarp,et al.  Atomic layer epitaxy growth of doped zinc oxide thin films from organometals , 1994 .

[20]  Makoto Konagai,et al.  Atomic layer deposition of ZnO transparent conducting oxides , 1997 .

[21]  A. Ott,et al.  Atomic layer-controlled growth of transparent conducting ZnO on plastic substrates , 1999 .

[22]  E. Fortunato,et al.  Transparent Conducting Oxides for Photovoltaics , 2007 .