DLTS Analysis and Interface Engineering of Solution Route Fabricated Zirconia Based MIS Devices Using Plasma Treatment

Abstract

In this work, we have fabricated low-temperature sol–gel spin-coated and oxygen (O₂) plasma treated ZrO₂ thin film-based metal–insulator–semiconductor devices. To understand the impact of plasma treatment on the Si/ZrO₂ interface, deep level transient spectroscopy measurements were performed. It is reported that the interface state density (D _it) comes down to 7.1 × 10¹⁰ eV⁻¹ cm⁻² from 4 × 10¹¹ eV⁻¹ cm⁻², after plasma treatment. The reduction in D _it is around five times and can be attributed to the passivation of oxygen vacancies near the Si/ZrO₂ interface, as they try to relocate near the interface. The energy level position (E _T) of interfacial traps is estimated to be 0.36 eV below the conduction band edge. The untreated ZrO₂ film displayed poor leakage behavior due to the presence of several traps within the film and at the interface; O₂ plasma treated films show improved leakage current density as they have been reduced from 5.4 × 10⁻⁸ A/cm² to 1.98 × 10⁻⁹ A/cm² for gate injection mode and 6.4 × 10⁻⁸ A/cm² to 6.3 × 10⁻¹⁰ A/cm² for substrate injection mode at 1 V. Hence, we suggest that plasma treatment might be useful in future device fabrication technology.