PowerSemiconductorDevicesandSmartPowerICs..doc

Answers of Questions Chapter 1 Please classify the power semiconductor discrete devices. A: power rectifiers and power switches. 功率整流器和功率开关 Please list the name of popular power switch. A: power MOSFET, power BJT, IGBT, etc. 功率MOS管，功率BJT管，IGBT等 Define the ideal power semiconductor device. A: It must be able to control the flow of power to loads with ZERO power dissipation. 零功耗（包括导通损耗，关断损耗，开关损耗，均为零） Drawing out the switching waveform of ideal power switch. A: List the device name you known that has the normally-off performance. A: Normally-off: BJT, Enhancement MOSFET, VDMOS, Trench MOS, IGBT, Normally-on: JFET, Depletion MOSFET. Which is preferable for normal system, normally-on device or normally-off? Give the reason. A: For normal system, normally-off device is preferable as it has the power dissipation lower than normally-on device’s. 常关器件更好。因为开通功耗（有电流）大于关断功耗（近似无电流），所以常关器件比常开器件具有更低功耗。 List the international semiconductor company name you know that products the power semiconductor devices. A: TI, Onsemi, Freescale, Fairchild, ST, Infineon, NXP, Vishay, ADI, Maxim, ROHM List the special points of power semiconductor devices comparing with the digital semiconductor devices. A: higher voltage and larger current, bigger/special process technology, longer life cycle. 功率器件通常应用在高压、大电流环境，大线宽、特殊工艺，生命周期长。 数字器件通常应用在低压、小电流环境，小线宽、标准工艺，生命周期短。 Chapter 2 2-1. what is meant by impact ionization coefficient of hole(electron)? 耗尽区内，一个空穴（电子）在电场作用下，通过1cm的长度上产生的电子-空穴对的数目，定义为空穴（电子）的碰撞电离系数()。 2-2. what is a plane junction? 平行平面结是一维二极管，理想PN结，具有一维性质的电场。 2-3. define the punch-through diode structure. PiN二极管，反向耐压最大时i区全耗尽，称为穿通型二极管结构。 2-4. why does the impact ionization coefficient increase with the increasing of the electric field and it decrease with the increasing of temperature？ 碰撞电离系数是电场的强函数()∝E7，电场增加碰撞电离系数增大；随着温度升高，晶格振动加剧，载流子更容易与晶格碰撞失去能量，产生的电子-空穴数目减少，所以温度升高碰撞电离系数减小。 2-5. 一个电子（空穴）在耗尽区内与晶格原子发生碰撞，产生一个电子-空穴对，器件即发生雪崩击穿， 2-6. Which structure has the largest brea