Investigation of Asymmetric Characteristics of Novel Vertical Channel-All-Around (CAA) In-Ga-Zn-O Field Effect Transistors

This work reports the comprehensive study on asymmetric characteristic based on proposed stackable vertical Channel-All-Around (CAA) In-Ga-Zn-O field-effect transistors (IGZO FETs). Sufficient experimental data are analyzed for the reason of performance distinction between normal and reversed source/drain setup. Contact profile has great impacts on device characteristics such as short-channel effects and drain-induced barrier lowering (DIBL) due to different electric filed distributions in the IGZO channel near Schottky barrier. That is mainly caused by different etch process for upper and bottom electrodes, which doesn’t exist in planar structures. Furthermore, a 3-D technology computer-aided design (TCAD) device model is established. Interface defects are applied for slight variation in contact potential to verify the accuracy. Related analysis of contact barriers has been done based on simulation results. What’s more, channel length and etching depth of bottom electrode are also play a role in asymmetric characteristics, which could be applied as a reference to improve devices performance.