Electrical Properties and Charge Transport in the Pd/Al₂O₃/InGaAs MOS Structure

Abstract

The paper presents the results of a study focused on electrical properties and determination of transport mechanism through dielectric layer in Pd/Al2O3/In0.53Ga0.47As/InP MOS system. We found the current to be governed by Fowler-Nordheim tunneling in case of electron injection from the metal electrode for all dielectric thicknesses and of injection from the semiconductor for 10 nm Al2O3 thickness. The potential barrier for electrons at the metal-dielectric interface equals to 2.40±0.10 eV. The conduction band offset at the dielectric-semiconductor interface equals to 2.50±0.06 eV. The optimal value for Al2O3 oxide thickness among the MOS structures under study is proposed to be 10 nm. Increase of the Al2O3 thickness results in increase of fixed positive charge in the dielectric and probably extension of transition layer between the dielectric and semiconductor.

An investigation of capacitance-voltage hysteresis in metal/high-k/In0.53Ga0.47As metal-oxide-semiconductor capacitors

“…Table II summaries To further examine the physical location and distribution of the trapped charge, C-V hysteresis was measured as a function of oxide thickness series for (a) n-type and (b) ptype Pd/Al 2 O 3 (5-20 nm)/In 0.53 Ga 0.47 As MOS capacitors. 23 The use of a thickness series is useful in this respect, as for a trapped charge located in a plane within the oxide or at the oxide/semiconductor interface, the C-V hysteresis DV increases linearly with increasing oxide thickness. This linear relation can be expressed by the following equation:…”

“…The C ox values are based on oxide thickness values obtained from high-resolution cross-sectional transmission electron microscopy (HR-TEM), taking into account any interfacial oxide layers formed in the MOS structure. The following dielectric constant values were adopted, HfO 2 (21), 28 Al 2 O 3 (8.6), 23 and the native oxide of In 0.53 Ga 0.47 As (9). 29,30 …”

“…The issue of C-V hysteresis in the In 0.53 Ga 0.47 As MOS system has received only a limited amount of research attention to date. 23,24 The issue of C-V hysteresis is important from a technological perspective as it represents a physical process that results in device instability, and in addition, the level of charge trapping can be comparable to, or greater than, the effect of interface states for the In 0.53 Ga 0.47 As MOS system. 23 From a scientific perspective, the study of C-V hysteresis is of interest as it presents a method to analyse and quantify the density of charge trapping states in high-k oxides on III-V surfaces.…”