半导体物理与器件第7章到第13章名词解释.pdf

1 Abrupt junction approximation 突变结近似 The assumption that there is an abrupt discontinuity in space charge density between the space charge region and neutral semiconductor region 认为从中性半导体区到空间电荷区的空间电荷密度有一个突然的不连续 2 Depletion layer approximation 耗尽层近似 The number of carriers is almost zero due to the strong built in electric field in the space charge region that the charge in the space charge region is almost completely provided ionized impurity this space charge region is called depletion layer 由于空间电荷区较强的内建电场 载流子的数量几乎为零 因此可以认为空间 电荷区中的电荷几乎完全是由电离杂质所提供的 这种空间电荷区就称为耗尽层 3 Built in electric field 内建电场 An electric field due to the separation of positive and negative space charge densities in the depletion region 由于耗尽区正负空间电荷相互分离而形成的电场 4 Built in potential harrier 内建电势差 The electrostatic potential difference between the p and n regions of a pn junction in thermal equilibrium 热平衡状态下 pn 结内 p 区与 n 区的静电电势差 5 Depletion region space charge region barrier region 耗尽区 空间电荷区 势垒区 The region on either side of the metallurgical junction in which there is a net charge density due to ionized donors in the n region and ionized acceptors in the p region 冶金结两侧由于n区内施主电离和p区内受主电离而形成的带净正电与负电的 区域 详 pn 结界面两侧半导体中的载流子由于存在浓度差梯度而互相向对方区域 扩散 在 pn 结界面附近 n 区与 p 区分别留下了不可动的电离施主和电离受主杂 质离子 分别带有正负电荷 形成空间电荷区 在该区域中建立有电场 形成电 位差 产生相应的势垒 因此 pn 结空间电荷区又称为 pn 结势垒区 在势垒区中 载流子浓度趋于 0 即载流子基本 耗尽 因此又称为 耗尽层 6 Depletion layer capacitance junction capacitance barrier capacitance 耗尽层电 容 结电容 势垒电容 The capacitance of the pn junction under reverse bias 反向偏置下 pn 结的电容 7 Diffusion capacitance 扩散电容 The capacitance of a forward biased pn junction due to minority carrier storage effects 正偏 pn 结内由于少子的存储效应而形成的电容 详 对于正偏 pn 结 当外加偏压增加时 注入 n 区的空穴增加 在 n 区的空 穴扩散区内形成空穴积累 为保持电中性条件 扩散区内电子浓度也相应增加 电子注入 p 区情形类似 这种扩散区中的电荷随外加偏压变化而变化所产生的电 荷存储效应等效为电容 称为扩散电容 8 Diffusion conductance 扩散电导 The ratio of a low frequency small signal sinusoidal current to voltage in a forward biased pn junction 正偏 pn 结的低频小信号正弦电流与电压的比值 9 Diffusion resistance 扩散电阻 The inverse of diffusion conductance The ratio of a low frequency small signal sinusoidal voltage to current in a forward biased pn junction 扩散电导的倒数 正偏 pn 结的低频小信号正弦电压与电流的比值 10 Space charge width 空间电荷区宽度 The width of the space charge region a function of doping concentrations and applied voltage 空间电荷区延伸到 p 区与 n 区内的距离 它是掺杂浓度与外加电压的函数 11 Hyperabrupt junction 超突变结 A pn junction in which the doping concentration on one side decreases away from the metallurgical junction to achieve n specific capacitance voltage characteristic 一种为了实现特殊电容 电压特性而进行冶金结处高掺杂的 pn 结 其特点为 pn 结一侧的掺杂浓度由冶金结处开始下降 12 Linearly graded junction 线性缓变结 A pn junction in which the doping concentrations on either side of the metallurgical junction are approximated by a linear distribution 冶金结两侧的掺杂浓度可以由线性分布近似的 pn 结 13 Metallurgical junction 冶金结 The interface between the p and n doped regions of a pn junction pn 结内 p 型掺杂与 n 型掺杂的分界面 14 One sided junction 单边突变结 A pn junction in which one side of the junction is much more heavily doped than the adjacent other side 冶金结一侧的掺杂浓度远大于另一侧的掺杂浓度的 pn 结 详 若 pn 结面两侧为均匀掺杂 即由浓度分别为 N A 和 N D 的 p 型半导体和 n 型半导体组成的 pn 结 称为突变结 若一边掺杂浓度远大于另一边掺杂浓度 即 N A N D 或 N A N D 这种 pn 结称为单边突变结 15 Varactor diode 变容二极管 A diode whose reactance can be varied in a controlled manner with bias voltage 电容随着外加电压的改变而改变的二极管 16 Avalanche breakdown 雪崩击穿 The process whereby a large reverse bias pn junction current is created due to the generation of electron hole pairs by the collision of electrons and or holes with atomic electrons within the space charge region 电子和 或 空穴穿越空间电荷区时 与空间电荷区内原子的电子发生碰撞产 生电子 空穴对 在 pn 结内形成一股很大的反偏电流 这个过程就称为雪崩击 穿 详 在反向偏置时 势垒区中电场较强 随着反向偏压的增加 势垒区中电场 会变得很强 使得电子和空穴在如此强的电场加速作用下具有足够大的动能 以 至于它们与势垒区内原子发生碰撞时能把价键上的电子碰撞出来成为导电电子 同时产生一个空穴 新产生的电子 空穴在强电场加速作用下又会与晶格原子碰 撞轰击出新的导电电子和空穴 如此连锁反应好比雪崩一样 这种载流子数 迅速增加的现象称为倍增效应 如果电压增加到一定值引起倍增电流趋于无穷大 这种现象叫雪崩击穿 17 Tunnel breakdown 隧道击穿 齐纳击穿 Maybe top of the valence band of the p region is higher than the bottom of conduction band of the n region with the reverse bias voltage increases in heavily doped pn junction The electrons in valence band of the p region can directly reach the conduction band of the n region through the band gap by tunnel effect to become the carrier in the conduction band When the reverse bias voltage at the junction increases to a certain extent tunneling current will sharply increase showing breakdown called tunneling breakdown also known as Zener breakdown 对重掺杂 pn 结 随着反偏电压增大 可能使 p 区价带顶高于 n 区导带底 p 区价带的电子可以通过隧道效应直接穿过禁带到达 n 区导带 成为导带载流子 当结上反偏电压增大到一定程度 将使隧穿电流急剧增加 呈现击穿现象 称为 隧道击穿 又称为齐纳击穿 18 Carrier injection 载流子注入 The flow of carriers across the space charge region of a pn junction when a voltage is applied 外加偏压时 pn 结体内载流子穿过空间电荷区进入 p 区或 n 区的过程 19 Critical electric field 临界电场 The peak electric field in the space charge region at breakdown 发生击穿时 pn 结空间电荷区的最大电场强度 20 Forward bias 正偏 The condition in which a positive voltage is applied to the p region with respect to the n region of a pn junction so that the potential barrier between the two regions is lowered below the thermal equilibrium value p 区相对于 n 区加正电压 此时结两侧的电势差要低于热平衡时的值 21 Reverse bias 反偏 The condition in which a positive voltage is applied to the n region with respect to the p region of a pn junction so that the potential barrier between the two regions increases above the thermal equilibrium built in potential barrier pn 结的 n 区相对于 p 区加正电压 从而使 p 区与 n 区之间势垒的大小超过热 平衡状态时势垒的大小 22 Generation current 产生电流 The reverse bias pn junction current produced by the thermal generation of electron hole pairs within the space charge region pn 结空间电荷区内由于电子 空穴对热产生效应形成的反偏电流 23 long diode 长二极管 A pn junction diode in which both the neutral p and n regions are long compared with the respective minority carrier diffusion length 电中性 p 区与 n 区的长度大于少子扩散长度的二极管 24 short diode 短二极管 A pn junction diode in which at least one of the neutral p or n regions is short compared to the respective minority carrier diffusion length 电中性 p 区与 n 区中至少有一个的长度小于少子扩散长度的 pn 结二极管 25 Recombination current 复合电流 The forward bias pn junction current produced as a result of the how of electrons and holes that recombine within the space charge region 穿越空间电荷区时发生复合的电子与空穴所产生的正偏 pn 结电流 26 Reverse saturation current 反向饱和电流 The ideal reverse bias current in a pn junction pn 结体内的理想反向电流 27 Storage time 存储时间 The time required for the excess minority carrier concentrations at the space charge edge to go from their steady state values to zero when the diode is switched forward to reverse bias 当 pn 结二极管由正偏变为反偏时 空间电荷区边缘的过剩少子浓度由稳态值 变为零所用的时间 28 反型异质结 掺杂剂在冶金结处变化的异质结 29 同型异质结 掺杂剂在冶金结处不变的异质结 30 电子亲和规则 在一个理想的异质结中 导带处的不连续性是由于两种半导 体材料的电子亲和能不同引起的 31 异质结 两种不同的半导体材料接触形成的结 32 肖特基效应 镜像力降低效应 由于电场引起的金属 半导体接触处势垒 峰值降低的现象 33 欧姆接触 金属 半导体接触电阻很低 且在结两边都能形成电流的非整流 接触 34 肖特基接触 金属 半导体的整流接触 35 肖特基势垒高度 金属 半导体结中从金属到半导体的势垒 36 热电子发射效应 载流子具有足够的热能时 电荷流过势垒的过程 37 二维电子气 2 DEG 电子堆积在异质结表面的势阱中 在与表面垂直的 方向上有量子化能级 38 功函数 真空中静止电子的能量 E0 与费米能级 EF 之差 39 电子亲和能 使半导体导带底的电子逸出体外所需要的最小能量 40 金属 半导体功函数差 金属功函数和电子亲和能之差的函数 41 Transistor leakage current I CEO 晶体管漏电流 I CEO Base is open applied the reverse DC voltage of determined value at both ends of the collector emitter the detected current I CEO is the reverse leakage current of the measured transistor 基极开路 在集电极 发射极两端加一定值反向直流电压 此时检测到的电流 即为被测晶体管的反向漏电流 I CEO 42 Transistor saturation voltage V CES 晶体管饱和压降 V CES When the two junctions of the transistor collector junction emitter junction in the forward bias is called the transistor is saturated At this moment the voltage drop because of the obstruction of Collector junction to current is called the reverse saturation voltage denoted V CES 当晶体管的两个结 集电结 发射结 都处于正偏时 则称此晶体管处于饱和 状态 此时 由于集电结对电流的阻碍而产生的电压降 称为反向饱和压降 记 为 V CES 43 Bandgap narrowing 禁带变窄 The reduction in the forbidden energy bandgap with high emitter doping concentration 随着发射区重掺杂 禁带的宽度减小 44 High injection 大注入 If the injected non equilibrium minority carrier concentration is comparable to or even greater than the equilibrium majority carrier concentration it is called high injection 如果注入的非平衡少数载流子浓度与平衡多子浓度相比拟甚至大于平衡多子 浓度 称为大注入 45 Low injection 小注入 If the injected non equilibrium minority carrier concentration is far less than the equilibrium majority carrier concentration it is called low injection 如果注入的非平衡少数载流子浓度远小于平衡多子浓度的情况称为小注入 46 Small signal 小信号 The signal amplitude is low and meets the condition V Kt q 26mv 信号幅度很小 满足条件 V Nc 时 Nc 是集电区的掺杂浓度 则集电结的负空间电荷层将推移到集 电区内 即中性基区进一步展宽到集电区 这就是产生了 Kirk 效应 基区展宽 效应 54 Early voltage 厄尔利电压 The value of voltage magnitude at the intercept on the voltage axis obtained by extrapolating the I C versus V CE curves to zero current 反向延长晶体管的 I V 特性曲线与电压轴交点的电压的绝对值 55 Base region self bias effect 基区自偏压效应 The base region current flows level through the base region produces voltage drop in the active region let the potential close to the base bar and the potential away from the base bar are not equal And emitting region doping concentration is high the potential is equal so that the E B junction voltage drop is not equal this effect is caused by the active base region resistance r b1 called base region self bias effect 基区电流水平流过基区 在有源区上产生压降 使靠近基极条处的电势与远离 基极条处的电势不相等 而发射区掺杂浓度较高 电势相等 从而使 E B 结上压 降不相等 这种效应是由有源基区电阻 r b1 引起的 称为基区自偏压效应 56 Current crowding 电流集边 The nonuniform current density across the emitter junction areacreated by a lateral voltage drop in the base region due to a finite base current and base resistance 基极串联电阻的横向压降使得发射结电流为非均匀值 详 由于基区电阻导致基区自偏压效应 发射结而上不同位置的结压降不相等 离基极近的部分结压降大 注入的电流密度大 而离基极远的部分结压降小 注 入的电流密度小 如果情况严重 这一部分结面甚至没有电流注入 使发射结电 流集中位于离基极近的发射结边缘处 这一现象称为发射极电流集边效应 57 Cutoff 截止 The bias condition in which zero or reverse bias voltages are applied to both transistor junctions resulting in zero transistor currents 晶体管两个结均加零偏或反偏时 晶体管电流为零的工作状态 58 Cutoff frequency 截止频率 特征频率 f T The frequency at which the magnitude of the common emitter current gain is unity 共发射极电流增益的幅值为 1 时的频率 59 Alpha cutoff frequency 截止频率 The frequency at which the magnitude of the common base current gain is 1 2 of its low frequency value also equal to the cutoff frequency 共基极电流增益幅值变为其低频值的 1 2 时的频率 就是截止频率 60 Beta cutoff frequency 截止频率 The frequency at which the magnitude of the common emitter current gain is 1 2 of its low frequency value 共发射极电流增益幅值下降到其低频值的 1 2 时的频率 61 Base transit time 基区渡越时间 The time that it takes a minority carrier to cross the neutral base region 少子通过中性基区所用的时间 62 Collector depletion region transit time 集电极耗尽区渡越时间 The time that it takes a carrier to be swept across the B C space charge region 载流子被扫过 B C 结空间电荷区所需的时间 63 Collector capacitance charging time 集电极电容充电时间 The time constant that describes the time required for the B C and collector substrate space charge widths to change with a change in emitter current 随发射极电流变化 B C 结空间电荷区和集电区 衬底结空间电荷区宽度发生 变化的时间常数 64 Emitter base junction capacitance charging time E B 结电容充电时间 The time constant describing the time for the B E space charge width to change with a change in emitter current 发射极电流的变化引起 B E 结空间电荷区宽度变化所需要的时间 65 Forward active 正向有源 The bias condition in which the B E junction is forward biased and the B C junction is reverse biased B E 结正偏 B C 结反偏时的工作模式 66 Inverse active 反向有源 The bias condition in which the B E junction is reverse biased and the B C junction is forward biased B E 结反偏 B C 结正偏时的工作模式 67 Output conductance 输出电导 The ratio of a differential change in collector current to the corresponding differential change in C E voltage 集电极电流对 C E 两端电压的微分之比 68 堆积层电容 由于热平衡载流子浓度过剩而在氧化层下面产生的电荷 69 体电荷效应 由于漏源电压改变引起的沿沟道长度方向上的空间电荷宽度改 变所导致的漏电流偏离理想情况 70 沟道长度调制 当 MOSFET 进入饱和区时有效沟道长度随漏 源电压的改变 71 沟道电导 当栅源电压趋近于极限值 0 时 漏电流随着漏源电压