Comprehensive Study of Inversion Capacitance in Metal-Insulator-Semiconductor Capacitor with Existing Oxide Charges

• Published in: IEEE journal of the Electron Devices Society Vol. 10; p. 1
• Main Authors: Chen, Kung-Chu, Lin, Kuan-Wun, Huang, Sung-Wei, Lin, Jian-Yu, Hwu, Jenn-Gwo
• Format: Journal Article
• Language: English
• Published: New York IEEE 2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Capacitance; Capacitors; Depletion; Doping; Electrodes; frequency dependency; Frequency measurement; Insulators; lateral coupling; Mathematical models; metal-insulator-semiconductor (MIS); MIS (semiconductors); MIS devices; Modelling; oxide charges; Quantum confinement; Semiconductor process modeling; Simulation; Substrates
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2022.3215771

The impact of oxide charges on the metal-insulator-semiconductor (MIS) device's capacitance (C) and conductance (G) was studied in this work. A model to calculate MIS device's C and G under the considerations of oxide charges, doping concentration, device dimension, and AC signal frequency (ω) was proposed. A relation of C-CD∞ω-0.5 was found, where CD is the depletion capacitance under the electrode. The relation is examined by the experimental and the TCAD simulation. The capacitance of a MIS device with oxide charges can be calculated according to the proposed model and is well-matched with the TCAD simulation under light to moderate doping concentration. For heavily doped substrates, the modeling deviates from the simulation results because of quantum confinement and concentration-dependent mobility. However, the trend of the capacitance value is still able to be estimated by our modeling. From the modeling, it was found that for Qox/q=7.5×1010cm-2, the MIS capacitor with substrate doping concentration NA=1×1015cm-3 exhibits a long lateral AC signal decay length of 52 m at 1 kHz under the inversion region. The findings of this work are fundamental and are helpful for device engineering.