Fabrication and characterization of Si-based MOS devices

Abstract

Silicon is a lead component in modern technologies due to its relatively low cost, and stability under various conditions. Silicon-based metal oxide semiconductor (MOS) structures have applications in elds varying from solar cells to gas sensors. Currently, silicon dioxide (SiO2) is preferred as there is high control over the oxide quality. As the demand for smaller scaled devices increases, the inability to form very thin SiO2 layers without inadverse e ects to device performance has become apparent. Aluminium oxide (Al2O3) is a high-k dielectric which has recently received renewed interest as a possible replacement for SiO2.

The presence of an oxide layer on silicon introduces traps at the oxide-silicon interface. Characterization of these defects is a necessary step to building a complete understanding of a device's performance. Manual characterization would be a time-consuming process which is prone to human error. A fully automated characterization system has been developed using LabVIEW. This system was used to characterize n-type silicon with SiO2 and Al2O3 interfacial layers over a large range of temperatures, voltages and frequencies. Traps at the interface have been found to have a large e ect on the capacitance and conductance of these devices, especially at high frequencies.