Charge Trapping In Gate Oxide Research Articles

Physical Origins and Analysis of Negative-Bias Stress Instability Mechanism in Polymer-Based Thin-Film Transistors

The physical origins of the negative-bias stress (NBS) instability in polymer-based thin-film transistors have been characterized. Through the quantitative analysis by TCAD simulation for the NBS time-dependent experimental results, the threshold voltage (VT)-shift by sub-bandgap density-of-states redistribution forms 70% and 78% for the measured total VT-shift while VT-shift by gate oxide charge trapping only takes 30% and 22% at NBS time of 3000 and 7000 s, respectively. In addition, the increase of source/drain Schottky contact resistance (RSD) is the main reason for NBS-induced on -current (ION) degradation.

Improvement of charge trapping by hydrogen post-oxidation annealing in gate oxide of 4H–SiC metal–oxide–semiconductor capacitors

The effect of hydrogen postoxidation annealing (POA) on the reliability of gate oxide formed in 4H–SiC metal–oxide–semiconductor (MOS) capacitors has been investigated. Argon POA at 1200 °C and hydrogen POA were carried out over a temperature range of 400–1000 °C to improve the properties of 4H–SiC/SiO2 interface and thermal gate oxide. Interface state density Dit decreases as the temperature of hydrogen POA increases and saturates at 800 °C. Additionally, the characteristics of charge trapping in gate oxide against the electron injection was greatly improved by the hydrogen POA above 800 °C. Hence, we can conclude that the hydrogen POA at high temperature is effective for improving the Dit and reliability of gate oxide formed in 4H–SiC MOS devices.

Mechanisms for hot-carrier-induced degradation in reoxidized-nitrided-oxide n-MOSFET's under combined AC/DC stressing

Hot-carrier-induced degradation behavior of reoxidized-nitrided-oxide (RNO) n-MOSFETs under combined AC/DC stressing was extensively studied and compared with conventional-oxide (OX) MOSFETs. A degradation mechanism is proposed in which trapped holes in stressed gate oxide are neutralized by an ensuing hot-electron injection, leaving lots of neutral electron traps in the gate oxide, with no significant generation of interface states. The degradation behavior of threshold voltage, subthreshold gate-voltage swing, and charge-pumping current during a series of AC/DC stressing supports this proposed mechanism. RNO device degradation during AC stressing arises mainly from the charge trapping in gate oxide rather than the generation of interface states due to the hardening of the Si-SiO/sub 2/ interface by nitridation/reoxidation steps.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>