私立中原大學八十八學年度博士班招生考試命題紙

所組別：

電子工程學系

科目：

半導體元件

考試時間：

06月09日第 1節

Each for 20 pts.

1. Consider a MOS capacitor with the following parameters:
   Calculate :(a)The oxide capacitance. (b)The surface potential when V_G=10 volts and there is no inversion charge. (c)The deep-depletion region width. (d)The depletion-layer charge.
   
   
2. Consider a gallium arsenide sample at . A Hall effect device has been fabricated with the following geometry:d=0.01 cm , W=0.05 cm , and L=0.5 cm . The electrical parameters are: I_x=2.5 mA, V_x=2.2 volts, and B_z=2.5*10^-2 tesla. The Hall voltage is V_H=-4.5mV. Find :(a)the conductivity type, (b)the majority carrier concentration , (c)the mobility , and (d)the resistivity.
   
   
3. Consider a silicon pn junction with the doping profile shown in Figure<1> .(a)Calculate the applied reverse-bias voltage required so that space charge region extends entirely through the p-region. (b)Determine the space charge with into the n⁺-region with the reverse-bias voltage calculated in part(a).(c)Calculate the peak electric field for this applied voltage.
   
   
   
4. A Schottky diode with n-type GaAs at yields the versus V_R plot shown in Figure<2> where is the capacitance per cm². Determine(a)V_bi ,(b)N_d , (c) , and (d).
   
   
   
5. 1. Consider an optical cavity. If N>>1, show that the wavelength separation between two adjacent resonant modes is .
      
   2. If the photon output of a laser diode is equal to the bandgap energy, find the wavelength separation between adjacent resonant modes in a GaAs laser with .

   Reference:

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