103 年 - 103 國立中山大學_碩士班招生考試_電機系(甲、乙、戊組)、電波領域：電子學#110218　

1. (25%) Consider an ideal Si p-n diode with abrupt junction at T = 300 K (V_T= 25.9 mV) for which the doping concentrations are N_A =. The cross-sectional area A = 100 μm². When this p-n diode is reverse biased with the reverse voltage V_R = 1 V, please calculate the depletion width of n-side W_n and p-side W_p, the charge stored on each side of the depletion region Q_J, the reverse saturation current Is and the junction capacitance C_j. Let Si intrinsic concentration n_i = 1.5 cm , and Si permittivity εsi = 11.7 x 8.85 xF/cm. Diffusion length and diffusion coefficient of electron in p-side are L_n = 10 pum and D_n= 18 cm²/s, respectively. Diffusion length and diffusion coeticient of hole in n-side are L_p = 5 um and D_p = 10 cm² /s, respectively. (W_n, W_p, Q_J, I_s, C_j: 5%*5)

3. (15%) Figure 2 shows a peak rectifier fed by a 100-Hz sinusoid having a peak value V_p = 120 V. The load resistance R = 20 kΩ. The output voltage shows a peal-to-peak ripple of 1.5V. Please calculate (1) the value of the capacitor C, (2) the fraction of the cycle during which the diode is conducting, (3) the average of the diode current. (5%, 5%, 5%)

4.(30%) Figure 3 shows the common-source amplifer with an ideal current source I = 0.4 mA, = 200 kΩ, R_G = 2 MΩ, R_D =R_L = 20 kΩ, C₁ = C₂ = C₃ = 1 HF. The MOSFET has the device parameters: I = 0.2 μm, W = 2 μm, = 10 fP/μm², μn = 450 cm²/V-s, r₀ = 100 kΩ, = 3.2 fF, can be neglected, and the source terminal of MOSFET is connected to its body terminal. Please calculate (1) the transconductance gm of the MOSFET, (2) the A_M，  f₁，f₂，f₃ (let f₁ ＜f₂＜f₃) values of the overall low- frequency transfer function , (3) the upper 3-dB frequency fr by using open-circuit time constants method. (5%, 5%*4, 5%)