哈罗 各位交大的精英朋友吗 小弟有几题 期末考的考题解不出来 想请教一下 会解的大大 帮忙po一下 拜托 ********************** 1. A one-side step junction (p+n) is built in silicon that has an avalance voltage of 500 V and Nd = 4.5 × 10^14cm-3, (a) if it is a“plane”junction what is the small signal capacitance/area just before breakdown?(b)if it is a “planar”junction, with a junction depth 1.0μm, what is the small signal capacitance/area just before breakdown? 2. Given a one-side n+p silicon with the following: A=10^-3 cm2 Na=10^16/cm3 Width of neutral p material = 5.0 μm Excess carrier lifetime throughout = 1.0 × 10^-6/sec T=27 C Calculate the total current under a 10-volts reverse bias. 3. Given the silicon pn junction diode with: p-type:Na = 10^16/cm3 μn= 1250 cm2/V．S Dn=32.5 cm2/S Ln=56.8 μm WE=10μm Short base n-type:Nd=10^16/cm3 μp=400 cm2/V．S Dp=10.5 cm2/S Lp =10.2 μm WB = 100μm Long base Calculate the amount of minority carrier charge in the neutral n-type side when the above diode is forward biased so that ideal diode current of 5 mA flows. 4. Given an n-pn prototype bipolar junction transistor with the following structure: Neutral emitter width = 2.0μm Neutral base width = 0.5μm Minority carrier lifetime in all portions of the device = 1.0μsec Base doping = 1.0*10^17/cm3 μnB =800cm2/V．S Collector doping 1.0×10^15/cm3 Cross section area = 10-3 cm2 BF = 100 Base transport factor =0.995 Calculate the emitter doping. Neglect any space charge region currents. 5. The accumulation and the high frequency invertion capacitances for an MOS capacitor with p-type silicon are 10 pF and 3 pF , respectively . Capacitance Area =10^-4 cm-2. Aluminum Metal with ΦM = 4.1eV. (a) Find the oxide thickness, tox(from the accumulation capacitance) (b) Find the maximum depletion depth (from the high frequency inversion capacitance). For (c) through (g) only,assume NA = 1.5*10^16cm-3. (c) Find ψp (d) Find the work function of the silicon. (e) Find the ideal flat band voltage assuming on oxide charge is present. (f) The measured VFB = -2.5V. Assume all of the oxide charge is fixed at the interface and find the surface charge density. (g) What is the sign(＋/－)of the charge calculated in (f) How do you know? 谢谢回答啦 ^^ --

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