| Summary: | The impact of oxide charges on the metal-insulator-semiconductor (MIS) device’s capacitance <inline-formula> <tex-math notation="LaTeX">$({C})$ </tex-math></inline-formula> and conductance <inline-formula> <tex-math notation="LaTeX">$({G})$ </tex-math></inline-formula> was studied in this work. A model to calculate MIS device’s <inline-formula> <tex-math notation="LaTeX">${C}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">${G}$ </tex-math></inline-formula> under the considerations of oxide charges, doping concentration, device dimension, and AC signal frequency <inline-formula> <tex-math notation="LaTeX">$(\omega)$ </tex-math></inline-formula> was proposed. A relation of <inline-formula> <tex-math notation="LaTeX">${C}-{C}_{\textrm {D}}\propto \omega ^{-0.5}$ </tex-math></inline-formula> was found, where <inline-formula> <tex-math notation="LaTeX">${C}_{\textrm {D}}$ </tex-math></inline-formula> 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 <inline-formula> <tex-math notation="LaTeX">$Q_{\textrm {ox}}/\textrm {q}=7.5\times 10^{10} \textrm {cm}^{\textrm {-2}}$ </tex-math></inline-formula>, the MIS capacitor with substrate doping concentration <inline-formula> <tex-math notation="LaTeX">$N_{\textrm {A}}=1\times 10^{15} \textrm {cm}^{\textrm {-3}}$ </tex-math></inline-formula> exhibits a long lateral AC signal decay length of <inline-formula> <tex-math notation="LaTeX">$52~\mu \text{m}$ </tex-math></inline-formula> at 1 kHz under the inversion region. The findings of this work are fundamental and are helpful for device engineering.
|
|---|