The C-V characteristic for an ideal MOS capacitor with cross-sectional area 10^-4 cm2 is shown below. The capacitor has a metal gate, SiO2 gate oxide, and silicon body. (a) Is the substrate doped p- or n-type? Why? (b) Calculate the gate oxide thickness. (c) Calculate the doping concentration in the Si substrate. (d) Draw the energy band diagram of the of the MOS capacitor at point A. (e) Calculate the capacitance (in Farads) at point B.
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The C-V characteristic for an ideal MOS capacitor with cross-sectional area 10^-4 cm2 is shown below. The capacitor has a metal gate, SiO2 gate oxide, and silicon body. (a) Is the substrate doped p- or n-type? Why? (b) Calculate the gate oxide thickness. (c) Calculate the doping concentration in the Si substrate. (d) Draw the energy band diagram of the of the MOS capacitor at point A. (e) Calculate the capacitance (in Farads) at point B.
![Q. 4 The capacitance-voltage (C−V) characteristic of a silicon MOS capacitor is shown in Figure Q4. The capacitor comprises a metal gate with a work function of 5.62 eV. The gate dielectric is made of silicon-dioxide (SiO2) with a relative permittivity of 3.9. (a) Sketch the block charge diagram corresponding to point (1) on the C - V curve. [4 marks] (b) If the capacitor area is 2×10−3 cm2, determine the oxide thickness. [3 marks] (c) Determine the depletion layer width at point (2). [4 marks] (d) Briefly describe two ways to reduce the threshold voltage of the capacitor. [4 marks] (e) If the flatband voltage is 0.7 V, determine the work function of the substrate. [3 marks] (f) Sketch the energy band diagram corresponding to point (2) on the C - V curve. Is the capacitor under accumulation, depletion, or inversion? Briefly explain. [7 marks] Figure Q4: Capacitance-voltage (C−V) characteristic of a silicon MOS capacitor.](https://www.doubtrix.com/uploads/editor/3301654154bUocnyQJRA.png)
