AVS 57th International Symposium & Exhibition
    Electronic Materials and Processing Wednesday Sessions
       Session EM+SS-WeA

Paper EM+SS-WeA4
An In Situ Examination of Atomic Layer Deposited Al2O3/InAs(100) Interfaces

Wednesday, October 20, 2010, 3:00 pm, Room Dona Ana

Session: High-k Dielectrics for III-V Electronics
Presenter: A.P. Kirk, University of Texas, Dallas
Authors: A.P. Kirk, University of Texas, Dallas
M. Milojevic, University of Texas, Dallas
D.M. Zhernokletov, University of Texas, Dallas
J. Kim, University of Texas, Dallas
R.M. Wallace, University of Texas, Dallas
Correspondent: Click to Email
An in situ half-cycle atomic layer deposition/X-ray photoelectron spectroscopy (ALD/XPS) procedure was conducted in order to learn more about the evolution of the Al2O3 dielectric interface with undoped InAs(100). Without breaking vacuum, monochromatic XPS was used to examine the InAs(100) surface following ammonium sulfide passivation or ammonium hydroxide etching and then after each individual ALD pulse of trimethyl aluminum (TMA) and deionized water (DIW) precursors (e.g. single TMA pulse/XPS scan; single DIW/XPS scan; etc.). Ammonium sulfide was more effective at minimizing native oxides than ammonium hydroxide. Regardless of chemical cleaning technique, after depositing up to 1 nm of Al2O3, elemental arsenic (Aso or As-As bonds) remained at the interface which may have adverse implications for devices such as metal oxide semiconductor field effect transistors (MOSFET). After heating to 300 °C (typical ALD reactor temperature), As-S bonding was reduced below the XPS detection limit. The In1+ chemical state (e.g. In2O) was preserved while trivalent In and As oxidation states were minimized following exposure to TMA. The chemical reaction pathways appear to be similar to that observed for GaAs and InGaAs. We will also present electrical characterization studies and examine the correlation to the in situ interface analysis.