Current voltage characterization of high-k oxide on InGaAs substrate

Abstract: Abstract Metal oxide semiconductor (MOS) capacitor was fabricated on the InGaAs substrate with Al2O3/HfO2 gate oxide. InGaAs is one of the promising candidates for advanced applications which require the lower power supply and high frequency. The high-k films (Al2O3/HfO2) were formed by atomic layer deposition (ALD) as an alternative to silicon dioxide (SiO2) to proceed the scaling of oxide to lower values of equivalent oxide thickness (EOT). To reduce the high leakage current HfO2 has been processed as a gate oxide while Al2O3 was used as an interlayer to improve the interface quality of high-k/InGaAs. The constant voltage stress (CVS) and ramped voltage stress (RVS) techniques were used to analyze the reliability of gate oxide in terms of stress induced leakage current and soft & hard breakdown. The analyzed conduction mechanism through high-k oxide represents the thermal dependence at high temperature but it was not fitted with PF-model neither with Schottky model. However, band to band tunneling was observed at lower temperature. Time to breakdown 6.13×102 s was also measured at 4.5 V constant voltage stress. Breakdown field of Al2O3 with oxide thickness 0.5 nm and HfO2 with oxide 4.5 nm thickness was observed by ramped voltage stress (RVS) technique. Under the positive applied bias the breakdown field for HfO2 and Al2O3 was 9.5 MV/cm and 26.4 MV/cm respectively. Similarly, under negative bias breakdown field for HfO2 and Al2O3 was 6.1 MV/cm and 17.2 MV/cm respectively.