Effects of carbon impurity in ALD-Al 2 O 3 film on HAXPES spectrum and electrical properties of Al 2 O 3 /AlGaN/GaN MIS structure

Abstract In this study, the effects of carbon impurity in the atomic layer deposited-Al 2 O 3 film on the hard X-ray photoelectron spectroscopy (HAXPES) spectra and the electrical properties of metal–insulator–semiconductor (MIS) structure were measured. The carbon concentration in the Al 2 O 3 film was adjusted by varying the deposition conditions (precursor: trimethylaluminum, Al(CH 3 ) 3 , or dimethylaluminum hydride, Al(CH 3 ) 2 H, oxidant, and deposition temperature) in the atomic layer deposition process. The HAXPES measurements revealed the correlation between full width at half maximum (FWHM) of Al 1 s and O 1 s spectra and the carbon concentration in the Al 2 O 3 film. Furthermore, the negative charges in the Al 2 O 3 film could change the FWHM, attributed to the carbon impurity. The correlation between the carbon concentration and the electrical characteristics of the Al 2 O 3 /AlGaN/GaN MIS structure was analyzed. The interface state density and the effective charge density were dependent on the carbon concentration in the Al 2 O 3 film.