AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM11
Attempts on Synthesizing Linear Atomic Metal Chains on GaN(0001)

Thursday, November 6, 2003, 11:40 am, Room 310

Session: Patterned Growth and Etching of Semiconductors
Presenter: C. Chang, National Taiwan University, R.O.C.
Authors: C. Lung, National Taiwan University, R.O.C.
C. Chang, National Taiwan University, R.O.C.
Correspondent: Click to Email
The continuing advances in miniaturization of semiconductor devices have seriously challenged the fields of materials processing and circuit designs. This work explores the chemical reaction involved in the possible formation of nanowires using a pyridylamino chelate that contains a linear atomic chain of chromium for CVD. The adsorption, surface reaction, and thermal pyrolysis of this metal string chelate on GaN(0001) were characterized using synchrotron radiation-induced core-level photoelectron spectroscopy, secondary ion mass spectrometry, and temperature-programmed desorption. Secondary ion mass spectrometric studies showed that pyridylamino trinuclear chromium complex may react with the GaN(0001) surface to produce pyridine and pyridylamino fragments even at a very low substrate temperature of less than 150 K. Upon increasing exposure of the trinuclear chromium metal-chain complex on GaN(0001), the Cr3p photoelectron profile altered substantially, revealing an evolution in bonding configuration of the chromium metal-chain chelate on the surface. At low exposures, the Cr3p profile contained three features, peaked at different binding energies, of equal areas. The number of distinguishable features in the Cr3p spectrum increased to five as the chelate coverage on GaN(0001) was increased to more than one monolayer. Increasing the substrate temperature not only caused a change of the bonding geometry of the chromium string on the surface but also induced decomposition of the chromium chelate in two different stages. Desorption of the dipyridylamino ligand took place at a substrate temperature of 340 K, while disruption of the chromium string occurred at about 540 K. Results of this work point to the possibility of forming chromium nanospecies on the semiconductor surface through vacuum chemical deposition using organometallic metal strings. The fundamental aspects and the formation of nanowires involved in the nano-contact technology will be discussed.