吴伟立 214_215_C5.doc

CHAPTER 5 The pn Junction and Metal-Semiconductor Contact B. Describe how the built-in potential barrier maintains thermal equilibrium.3. A. Sketch the energy-band diagram of the pn junction when a reverse-bias voltage is applied.B. Describe what happens to the space charge widths and electric field when a reverse-bias voltage is applied to the pn junction.C. Explain the source of junction capacitance.D. Describe the characteristics and properties of a one-sided pn junction.4. A. Describe the formation of a Schottky barrier junction in which ms. and define the Schottky barrier junction and built-in potential barrier.B. Sketch the energy-band diagram of a reverse-biased Schottky barrier junction.5. A. Sketch the energy-band diagram of a forward-biased pn junction and a forward biased Schottky barrier junction.B. Sketch the current-voltage characteristics of a pn junction diode and a Schottky barrier junction diode on the same plot. Describe similarities and differences.6. A. Sketch the energy-band diagram of an ideal nonrectifying contact with both n-type and p-type semiconductors. B. Sketch the energy-band diagram of a tunneling ohmic contact7. A. Describe how a linearly graded junction is formedB. Define a hyperabrupt junction.8. Describe the general procedure of fabricating a pn junction.REVIEW QUESTIONS1. Sketch the energy-band diagram of a zero-biased pn Junction.2. A. Why is the electric field a linear function of distance in a uniformly doped pn junction? What is the direction of the electric field? B. If Na Nd in a pn junction, is Xp Xn , Xn Xp, or Xn = Xp?C. How does the built-in potential barrier depend on the doping concentrations in the pn junction?3. A. In a reverse-biased pn junction, which side has the higher potential?B. Sketch the energy-band diagram of a reverse-biased pn junction. C. Why does the space charge width increase with reverse-bias voltage? D. Why does a capacitance exist in a reverse-biased pn junction? Why does the capacitance decrease with increasing reverse-bias voltage? E. What is a one-sided pn junction? What parameters can be determined in a one-sided junction?4. Sketch the energy-band diagram of a zero-biased rectifying metal-to-n-typesemiconductor contact. Define the Schottky barrier and built-in potential barrier.5. A. Sketch the energy-band diagram of a forward-biased pn junction.B. Why can charge flow across a forward-biased pn junction?6. A. Sketch the energy-band diagram of an ideal nonrectifying metal-semiconductor contact with a p-type semiconductor.B. Discuss the electron flow in a tunneling ohmic contact under both bias conditions7. A. What is a linearly graded junction?B. What is a hyperabrupt junction and what is one advantage or characteristic of such a junction?8. What are the various steps in the fabrication of a pn junction?译文第五章 PN结和半导体的连接B. 简述嵌入式势垒如何保持热力平衡。3. A. 画出PN结加反向偏压时的能带图。B. 描述PN结加反向偏压时空间电荷的宽度及电场的变化。C. 结电容的解释D. 描述单面PN结的特征与特性4. A. 描述当ms时的肖基特二极管并解释肖基特二极管及嵌入式势垒的定义。B. 画出肖基特二极管加反向偏压时的能带图。5. A. 画出加正向偏压时肖基特二极管和PN结的能带图。 B. 在同一张图上画出PN结二极管和肖基特二极管的伏安特性，并区分他们的相同点和不同点。6. A . 画出理想状态下N型半导体与P型半导体的非整流接触能带图。 B. 画出隧道效应的欧姆接触的能带图。7. A . 描述线性缓变结的形成。 B. 超突变结的定义。8. 简述制作PN结的一般步骤。问题回顾1. 画出无倾向性的PN结能带图。2. A. 为什么电场在PN结杂质浓度分布均匀时呈线性作用？指出电场的方向。B. 当PN结 Na Nd 时，是否 xp xn, xnxp, 或者xn=xp ？C. PN结内嵌势垒如何取决于半导体参杂浓度？3. A . 在加反向偏压的PN结，哪一边的势能更高？B . 画出反向偏压下PN结的能带图。C . 为什么空间电荷宽度随反偏电压变大而增大？D . 为什么在反偏电压PN结中存在电容量？为什么电容量和反偏电压呈反比？E . 什么叫单晶面PN结？单晶面PN结有什么特征？4. 画出zero-biased rectifying metal N型半导体连接的能带图。简述肖基特势垒和内嵌式势垒的定义。5. A . 画出加正向电压的PN结的能带图。B . 为什么电荷能穿过正偏电压PN结？6 . A . 画出理想状态下金属半导体与P型半导体连接的能带图。 B . 讨论电子在特殊条件下在隧道效应欧姆接触的流动。7 . A . 什么是线性缓变结？B . 什么是超突变结，它有什么优势或特性？8 . 组成PN结的几个步骤是什么？214PROBLEMSSection 5.2 The pn Junction-5.1 (a) Calculate Vbi in a silicon pn junction at T = 300 K for (a) Nd = lO15 cm-3 and Na = (i) 1015, (ii) lO16, (iii) 1017, (iv) 1018 cm-3. (b) Repeat part (a) for Nd = 1018 cm-35.2 Calculate the built-in potential barrier, Vbi, for Si, Ge, and GaAs pn junctions if they each have the following dopant concentrations at T = 300 K:(a) Nd = 1014 cm-3 Na = 1017 cm-3 (b) Nd = 5 1016 Na = 5 1016(c) Nd = 1017 Na = 10175.3 (a) Plot the built-in potential barrier for a symmetrical (Na = Nd ) silicon pn junction at T =300 K over the range 1014 Na = Nd 10l9 cm-3 . (b) Repeat port (a) for a GaAs pn junction.5.4 Consider a uniformly doped GaAs pn junction with doping concentrations of Na = 5 x 1018 cm-3 and Nd = 5 1016 cm-3. Plot the built-in potential barrier voltage, Vbi, versus temperature for 200 T 500 K.5.5 An abrupt silicon pn junction at zero bias has dopant concentrations of Na = 1017 cm-3 and Nd = 5 X 10l5 cm-3. T = 300 K.(a) Calculate the Fermi level on each side of the junction with respect to the intrinsic Fermi level.(b) Sketch the equilibrium energy-band diagram for the junction and determine Vbi from the diagram and the results of part (a). （c） Calculate Vbi using Equation (5.10), and compare the results to part (b).(d)Determine xn, xp, and the peak electric field for this junction.5.6 Repeat problem 5.5 for the case when the doping concentrations are Na = Nd = 2 1016 cm-3.5.7 A silicon abrupt junction in thermal equilibrium at T = 300 K is doped such that EC-EF = 0.21 eV in the n region and EF-Ev = 0.18 eV in the p region. (a) Draw the energy band diagram of the pn junction. (b) Determine the impurity doping concentrations in each region. (c) Determine Vbi5.8 Consider the uniformly doped GaAs junction at T = 300 K.At zero bias, only 20 percent of the total space charge region is to be in the p region. The built-in potential barrier is Vbi = 1.20 V. For zero bias, determine (a) Na ,(b) Nd , (c) Xn, (d) xp and (e) max5.9 Consider the impurity doping profile shown in Figure P5.9 in a silicon pn junction .For zero applied voltage, (a) determine Vbi, (b) calculate xn and xp, (c) sketch the thermal equilibrium energy band diagram, and (d) plot electric field versus distance through the junction.5.10 A uniformly doped silicon pn junction is doped to levels of Nd = 5 X 1O15 cm-3 and Na = l016 cm-3. The measured built-in potential barrier is Vbi = 0.40 V. Determine the temperature at which this result occurs. (You may have to use trial and error to solve this problem.)5.11 Consider a uniformly doped silicon pn junction with doping concentrations Na = 5 1017 cm-3 and Nd = 1017 cm-3. (a) Calculate Vbi at T = 300 K. (b) Determine the temperature at which Vbi, decreases by 1 percent.5.12 An “isotype” step junction is one in which the same impurity type doping changes from one concentration value to another value. An n-n isotype doping profile is shown译文问题5.2 PN结- Zero Applied Bias5.1 (a) 一个硅PN结在T=300K时，Nd = lO15 cm-3 ， Na = (i) 1015, (ii) lO16, (iii) 1017, (iv) 1018 cm-3. (b) 重复（a）步骤当Nd = 1018 cm-3 5.2 Si, Ge,和 GaAs PN结在T=300K，分别都含有下列参杂浓聚物，计算势垒Vbi ： (a) Nd = 1014 cm-3 Na = 1017 cm-3 (b) Nd = 5 1016 Na = 5 1016(c) Nd = 1017 Na = 10175.3 （a）在1014 Na = Nd 10l9 cm-3 范围内划出均匀硅PN结在T=300K时的势垒 ，（b）换为砷化镓PN结， 重复(a)步骤。5.4 考虑材料均匀掺杂浓度砷化镓PN结Na= 5 x 1018 cm-3和Nd= 51016cm-3。画出内置的势垒电压，Vbi ，相对温度 200 T 500 K.5.5 突变硅PN