The bonding chemistry of various GaAs-to-oxide/GaAs bonded samples was investigated using multiple internal transmission Fourier transform infrared spectroscopy for thermally annealed and thermocompression annealed samples. The oxides used in these investigations included a native GaAs oxide as well as two compositions of borosilicate glass ͑BSG͒ deposited by low-pressure chemical vapor deposition ͑LPCVD͒. For the thermally annealed samples, the hydrogen-bonded H 2 O/OH groups on the hydrophilic surface form a room temperature bond without the application of pressure. Chemical changes at the wafer-bonded interface occur in two temperature regions. For anneals between 200 and 400°C for 1 h in N 2 , the H 2 O/OH groups react and evolve H that becomes absorbed within the oxide. The LPCVD BSG oxide was chemically unaltered during anneals in this temperature range, however, the GaAs native oxide underwent chemical modification. Initially, the GaAs oxide consisted of As͑III͒-O and Ga-O related oxides. The As͑III͒-O oxides react to form free As and Ga-O during annealing between 200 and 400°C. For anneals between 500 and 600°C, the reaction of H 2 O/OH groups continue and the H becomes infrared inactive, most likely forming H 2 voids at the bonded interface. In addition, As͑V͒-O related oxides were observed during thermal annealing in this temperature range. No detectable chemical changes in the BSG were observed over the temperature range investigated. Samples that were annealed under an estimated 1-10 MPa of pressure had similar chemical changes to thermally annealed samples.
Articles you may be interested inIn situ diagnostics for studying gas-surface reactions during thermal and plasma-assisted atomic layer deposition J. Vac. Sci. Technol. A 30, 01A158 (2012); 10.1116/1.3670404Plasma polymerized thin films of maleic anhydride and 1,2-methylenedioxybenzene for improving adhesion to carbon surfaces
Plasma-treated and DI H2O rinsed oxide layers are commonly used in wafer bonding applications. Borosilicate glass (BSG) layers deposited by low-pressure chemical vapor deposition (LPCVD) treated with an O2 plasma in reactive ion etching (RIE) mode at 0.6 W/cm2 and rinsed with DI H2O readily bond to GaAs and Si. The chemical role of this pre-bonding treatment was investigated using attenuated total reflection Fourier transform infrared (ATR- FTIR) spectroscopy. The peak intensities for both the Si-O and B-O absorbance bands decreased in intensity as a result the plasma treatment consistent with the uniform sputter etching of BSG. The effect of changing the total plasma treatment time was investigated in terms of the total amount of material removed. Polarization-dependent ATR-FTIR revealed that the H2O/OH absorbance bands decreased in peak intensity with the OH groups preferentially oriented perpendicular to the sample surface after the plasma treatment. The subsequent DI H2O rinse restores the water to the surface while changing the surface BSG composition. ATR-FTIR studies suggest that for oxide compositions greater than 10 mole % B2O3, the top 4 nm of B2O3 was removed or leached from the oxide layer during the DI H2O rinse.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.