Variations of electron traps in bulk n-GaAs by rapid thermal processing

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Abstract
Rapid thermal processing (RTP) using halogen lamps for liquid encapsulated Czochralski grown GaAs doped with Si has been studied by deep‐level transient spectroscopy, capacitance‐voltage, and photoluminescence measurements. RTP is performed at 700, 800, and 900 °C for 6 s with and without SiO2 encapsulation. Three electron traps ED1(Ec −0.26 eV), ED2(Ec −0.49 eV), and ED3(Ec −0.55 eV) are produced depending on RTP conditions. The trap ED1 is observed in all RTP samples, and its depth profiles vary with RTP conditions. The decrease of the shallow donor concentration occurs for RTP samples above 800 °C, especially for those without encapsulation. It is thought that these results, which are peculiar to the RTP method, are related to the production of As interstitials and As vacancies by the large thermal stress induced by the rapid heating for RTP. The decrease of the concentration of trap EL2(Ec −0.81 eV) is not observed with RTP as reported in the furnace processing. This is due to the effect of the short‐time processing of RTP.