DIELECTRIC PROPERTIES OF MOS DEVICE BASED ON TiO2/SiO2 OXIDE LAYER

The metal-oxide-semiconductor (MOS) structure consists of a metal contact separated from the semiconductor by a dielectric material. In this study, the MOS device with double oxide layer was fabricated. The dielectric properties of the MOS device based on TiO2 (100 nm)/SiO2 (10 nm) oxide layer have been investigated by using the frequency dependent admittance (Y=G+iωC) measurements. For electrical measurements, the both ohmic back and rectifier front contacts were formed by thermal evaporation system using high purity Au (99.999%) metal with thickness of 150 nm. The admittance measurements were carried out in the frequency range of 1 kHz – 5 MHz and at room temperature. The values of dielectric parameters such as dielectric constant (????′), loss (????′′), loss tangent (???????????? ????), ac conductivity (????????????) and complex modulus (????∗) of the MOS device were calculated using the capacitance and conductance data [1-3]. The experimental results show that the ????′ and ????′ ′ values decrease with increasing frequency. Moreover, the ???????????? value increases with increasing frequency.