AVS 59th Annual International Symposium and Exhibition
    Electronic Materials and Processing Monday Sessions
       Session EM+TF+OX+GR-MoA

Paper EM+TF+OX+GR-MoA9
AR-XPS Study of Al2O3/In-based III-V Interfaces after Annealing under Vacuum at Low Temperature

Monday, October 29, 2012, 4:40 pm, Room 009

Session: High-k Dielectrics for MOSFETS II
Presenter: E. Martinez, CEA, LETI, MINATEC Campus, France
Authors: E. Martinez, CEA, LETI, MINATEC Campus, France
H. Grampeix, CEA, LETI, MINATEC Campus, France
O. Desplats, CEA, LETI, MINATEC Campus, France
A. Herrera-Gomez, CINVESTAV-Unidad Queretaro, Mexico
O. Ceballos-Sanchez, CINVESTAV-Unidad Queretaro, Mexico
J. Guerrero, CEA, LETI, MINATEC Campus, France
K. Yckache, CEA, LETI, MINATEC Campus, France
F. Martin, CEA, LETI, MINATEC Campus, France
Correspondent: Click to Email
III-V semiconductor substrates are a potential solution for MOSTETs down scaling below the 16 nm technological node. Indium based semiconductors, such as InGaAs, InAs and InP are promising compounds to improve the speed of operation. The quality of the interface between these high mobility substrates and the gate oxide is of crucial importance to preserve the devices electrical properties. Aluminium oxide is used to remove the As oxide (“self-cleaning” effect). The gate-last scheme is preferred to control of the high-k/III-V since it involves low temperature post deposition annealing [1]. State-of-the-art control of this interface has been obtained with annealing at 400°C under vacuum [2].In this work we focus on the impact of low temperature annealing under vacuum on the quality of the Al2O3/In-based III-V interfaces. We have studied the interfacial oxides formed between alumina and III-V substrates such as InGaAs, InAs and InP. Annealing at 600°C under ultra high vacuum (UHV) is first performed and compared to thermal treatments at 600°C and 400°C at 3 10-4 mbar. Substrate passivation is done with NH4OH (4 %). The 3-nm thick alumina is deposited by Atomic Layer Deposition (ALD) using TMA and H2O as precursor and oxidant. Angle-resolved photoelectron spectroscopy (AR-XPS) has been carried out to investigate the interfacial chemical bonding states. Consistent and robust analysis of the As 3d, P 2p, Ga3d and In 3d core levels was carried out through the simultaneous fitting method [3]. At 600°C, we show that, on InGaAs, no interfacial oxides are created after annealing under UHV, whereas a thin interfacial InGaOx is observed under secondary vacuum. A clear difference between the three substrates is observed after annealing at 400°C under 3 10-4 mbar. In particular, the indium oxidation and the relative stability of interfacial oxides are substrate dependant. On InAs, indium hydroxide is formed after annealing, by OH release from TMA/H2O deposited alumina. This is not the case with additional elements such as Ga and P, which react with residual species to create their respective oxides. On InGaAs, a regrowth of InGaOx is observed after anneal, as a result of preferential oxidation of Ga. On InP, the InPOx interfacial oxide seems to decrease after anneal.AcknowledgementsThis work was performed with financial support from the MOS35 project funded by the French National Research Agency. Measurements were carried out at the NanoCharacterization Centre (NCC) of MINATEC. [1] H. Zhao et al., Appl. Phys. Let. 95, 253501 (2009)[2] Y. Urabe et al., Appl. Phys. Let. 97, 253502 (2010)[3] J. Muñoz-Flores et al., J. Electron. Spec. Rel. Phen. 182, 81 (2011)