Dielectric response of crystalline tris(acetylacetonato)cobalt(III) films grown on Si substrate for low-k dielectric applications

Thin films of the complex tris(acetylacetonato)cobalt(III) [abb. Co(acac)3] were deposited in vacuum on glass and p-Si substrates for optical and dielectric studies. The samples were characterised by X-ray diffraction and fluorescence methods as well as optical absorption spectroscopy. The prepared films show a polycrystalline of monoclinic P21/c structure. The optical absorption spectrum of the prepared film was not exactly fit to that of the molecular one. The energy of the optical absorption onset of the Co(acac)3 film was calculated by using usual solid-state methods. For electrical measurements on the complex as insulator, samples in the form of metal–insulator–semiconductor (MIS) structure were prepared and characterised by measurement of the capacitance as a function of gate voltage at 1 MHz. The frequency dependence of the complex dielectric constant of the complex was studied in the frequency range (1–1000 kHz) in the temperature range (294–323 K). The experimental results were analysed in the framework of Debye single relaxation model. Generally, the present study shows that a film of complex Co(acac)3 grown on Si substrate is a promising candidate for low-k dielectric applications, it displays low-k value around 1.7 at high frequencies.

Tris(acetylacetonato)cobalt(III) complex of chemical formula Co(CH3COCHCOCH3)3 with structure shown below, was prepared in the form of thin film on p-Si substrate by sublimation method. Samples were characterised by X-ray diffraction and fluorescence. Their dielectric properties were studied as a function of frequency.Figure optionsDownload as PowerPoint slide