The deposition and characterization of high dielectric constant films prepared by pulsed reactive DC magnetron sputtering technique

High dielectric constant films are attractive not only for memory applications such as dynamic random access memory (DRAM) but also for use in integrated passive components. Integration of passive devices into advanced electronic applications is very attractive from both performance and cost perspectives. For such applications, the low temperature deposition and characterization in the appropriate operating frequency range are necessary. In this work, tantalum oxide films were deposited using pulsed reactive DC sputtering at room temperature. The broad range characterization of the tantalum oxide films was done using a test vehicle designed for high frequency measurement (up to 40 GHz). Also, the fundamental properties of the dielectric film 20 were addressed confirming an empirical equation, $EBV=203r$. This gives a design boundary for the capacitors, where E_BV is the is the breakdown field strength (MV/cm) and $3$ dielectric constant of the material.; The physical, optical and structural properties of the tantalum oxide films were studied as a function of oxygen percentage in the sputtering atmosphere. The deposition process was optimized in terms of the cathode voltage during the sputtering process with oxygen content and the pulsing condition of the target. The dielectric constant of the tantalum oxide thin films ranged from 19 (P = 100% O₂) to 31 (P = 35% O₂) at 1MHz The leakage current density was 4.96 nA/cm2 at P = 60% O₂ and 0.5 MV/cm electric field. The dielectric breakdown field strength was 3.8 MV/cm or higher with P = 60% O₂.; In the high frequency characterization, it is necessary to separate the genuine dielectric property of the thin film from the effects of the parasitic effects, such as resistance and inductance of the parallel capacitor, can be explained in an equivalent circuit model which realistically represent the measured data. The frequency behaviors of the tantalum oxide films were investigated to verify the non-dispersion behavior of the dielectric films using a test vehicle. In the present study, S₂₁(forward transmission coefficient) was used to measure the capacitance in the high frequency range. The dielectric constant (∼23) of the tantalum oxide films up to 10 GHz were successfully obtained and no dispersion was observed.