Surface Passivation of GaAs Substrates with SiO2 Deposited Using ALD

Dalapati GK; Chia CK; Mahata C; Das T; Maiti CK; Kumar MK; Gao H; Chiam SY; Tan CC; Chua CT; Cheng YB; Chi DZ

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Electrochemical and Solid State Letters, Vol.14, No.10, G52-G55, 2011

Surface Passivation of GaAs Substrates with SiO2 Deposited Using ALD

Dalapati GK, Chia CK, Mahata C, Das T, Maiti CK, Kumar MK, Gao H, Chiam SY, Tan CC, Chua CT, Cheng YB, Chi DZ

Feasibility of using atomic layer deposited (ALD) silicon dioxide (SiO2) as interface passivation layer in bulk-GaAs and epitaxial-GaAs (epi-GaAs) substrate is studied. The interfacial reaction mechanisms of ALD SiO2 on bulk-GaAs and epi-GaAs are studied using x-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and electrical measurements. Higher oxidation states of Ga (Ga2+, Ga3+) and As-O bonding are found to get effectively suppressed in ALD SiO2/GaAs structures after post deposition annealing. Capacitance-voltage characteristics of the TaN/ALD SiO2/p-GaAs gate stack show low hysteresis (similar to 30 mV) compared to ALD HfO2 on bulk p-GaAs. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615963] All rights reserved.