AVS 51st International Symposium
    Semiconductors Thursday Sessions
       Session SC+EM-ThM

Paper SC+EM-ThM1
HVP-CVD: A Novel Chemical Vapor Deposition Approach for Zinc Oxide Synthesis

Thursday, November 18, 2004, 8:20 am, Room 304B

Session: Wide Bandgap Semiconductors
Presenter: T.M. Barnes, Colorado School of Mines
Authors: T.M. Barnes, Colorado School of Mines
J. Leaf, Colorado School of Mines
C. Fry, Colorado School of Mines
C.A. Wolden, Colorado School of Mines
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Zinc oxide (ZnO) is a versatile II-VI semiconductor that has generated tremendous interest due to its unique combination of optical, electronic and mechanical properties. High vacuum plasma-assisted chemical vapor deposition (HVP-CVD) is introduced as a novel technique for the deposition of zinc oxide and the study of the associated surface chemistry. An inductively coupled plasma (ICP) source was used for the generation of atomic oxygen and other radicals. Radicals from the ICP source and organometallic precursors diffuse into a high vacuum environment where they combine to form metal oxide thin films on a heated substrate. The process is differentiated from conventional CVD approaches in that the collisionless environment precludes gas-phase reactions with the metal precursor. Advantages of the HVP-CVD approach were demonstrated for zinc oxide growth using dimethyl zinc. Notable achievements include high growth rates of highly oriented material, room temperature formation of (002)oriented ZnO, and nitrogen doping. The underlying process chemistry was investigated using a combination of in-situ diagnostics and ex-situ materials characterization. Optical emission spectroscopy (OES) and quadrupole mass spectrometry (QMS) were used to monitor the ICP source and deposition environment, respectively. In the case of intrinsic ZnO, the growth kinetics were found to be first order in dimethyl zinc and zero order in atomic oxygen. QMS analysis suggests that growth proceeds through an elegant pathway in which the methyl ligands simply desorb without oxidation. Nitrogen doping was achieved by replacing oxygen with N@sub 2@O in the ICP source. The mechanism of nitrogen incorporation is discussed in light of film properties and characterization of the deposition environment.