Characterization and Compact Modeling of Flicker Noise and Piezoelectric Effect in Advanced Field Effect Transistors

Identifier:  TDX:2982

Handle: https://hdl.handle.net/20.500.11797/TDX2982

Authors:  Muhea, Wondwosen Eshetu

Abstract:
Physically-based compact modeling of Thin Film and High Electron Mobility Transistors (TFTs, HEMTs) is targeted in this thesis. Firstly, DC and low-frequency noise characterization of ESL a-IGZO and polymeric organic TFTs have been performed for identifying the physical origin of 1/f noise. The experimental data analysis reveal random carrier exchange between gate oxide traps and the channel is the source of the Flicker noise in both types of TFTs. While noise from remote Coulomb scattering of carriers is observed at high current regions in the a-IGZO TFTs, the contact resistances have no contribution in both devices. Based on these results, DC and 1/f noise models are derived for the a-IGZO TFTs using the UMEM DC parameter extraction and unified Flicker noise modeling approaches. Secondly, piezoelectric effect modeling in AlGaN/GaN HEMTs is performed. By solving Poisson’s equation in each layer of the HEMT structure and assuming that the 2DEG electrons originate from surface states present on the AlGaN top, analytical Schottky barrier height and threshold voltage (Vth) expressions are developed. Effects of the AlGaN layer Aluminum content, GaN-cap layer, and AlN interlayer are considered. The Vth models are implemented in a previously developed I-V model for DC characteristics simulation. Finally, Various a-IGZO TFT and HEMT devices are employed to validate the proposed DC, 1/f noise, and Vth models. Model-experimental data gives excellent results in all operating regimes of the devices.