【作者】 陈文锁；

【导师】 张波；

【作者基本信息】 电子科技大学 ， 微电子学与固体电子学， 2012， 博士

【摘要】 众所周知，绝缘栅双极性晶体管（Insulated Gate Bipolar Transistor，IGBT）具有驱动功耗低、导通能力强、热稳定性好、耐压特性高和安全工作区大等优点，既能做成分立器件，又可以集成在体硅基或SOI（Silicon On Insulator）基的功率集成电路中，广泛的应用于各种电力电子系统，是电导调制新型半导体功率器件的典型代表器件。电导调制效应使IGBT具有较低导通压降，但与依靠多数载流子输运的MOSFET（Metal-Oxide-Semiconductor Field Effect Transistor）器件相比，漂移区存储的大量非平衡电子空穴对使IGBT关断速度明显减慢，限制了应用频率并增加了开关损耗，成为IGBT进一步应用的主要障碍。寻找提高IGBT关断速度的新理论和新方法，改善“导通压降-关断时间”之间的约束关系成为迄今尚待更好解决的基本问题。本文针对此约束关系，以SOI基高速横向IGBT器件（SOI LIGBT）为具体研究对象，采用由多数载流子输运的单极导通模式向非平衡载流子输运的双极导通模式转变的电势控制解析分析、数值仿真和实验验证三者相结合的方法，对LIGBT新技术和新结构开展深入研究，提出高速LIGBT电势控制（PA，Potential-Adjusted）理论及其两类新结构：电势控制高速LIGBT器件和三维电势控制高速LIGBT器件。主要创新点如下：第一、提出高速LIGBT电势控制（PA）理论（IEEE Electron Device Letters，2010年5月）。给出的电势控制PA区新概念，用以调节导通态内置逆向二极管结构的电势分布、构造关断态非平衡载流子的抽出通道，从而改善器件导通态和关断态的电特征，实现器件的无振荡开启、大电流导通和高速关断特性。高速LIGBT电势控制技术及其指导设计的两类新结构都是通过增大导通态时内置逆向二极管结构在阳极区部分的电势分布，达到降低由单极导通模式向双极导通模式转变的转变点阳极电压、消除Snapback现象、增大导通电流，同时实现关断态时非平衡载流子的抽出效应、提高关断速度，优化了导通压降和关断时间之间的约束关系。表达式V_sb=（1+K·r）V0给出了转变点阳极电压V_sb和空穴激发注入压降V0（硅材料约为0.7V）之间的关系，说明PA技术指导高速LIGBT器件设计的主要思路是减小电势控制因子r或三维调节因子K。典型新结构：双通道三维PA区阳极高速LIGBT器件（NPN-NCA-LIGBT），在消除Snapback现象和保持大导通电流能力的前提下，转变点阳极电压降至约Vsb=1.1V；并且，NPN-NCA-LIGBT与部分NPN控制阳极LIGBT器件（SA-NPN-LIGBT）和常规LIGBT器件的关断时间的比值分别为1:1.57和1:35.58。第二、提出电势控制高速LIGBT器件。通过提高PA区的电势分布减小电势控制因子r的取值，该类新结构包括：（1）PA区阳极高速LIGBT器件（NCA-LIGBT），清楚的展示了电势控制PA区创新性概念在高速LIGBT器件设计中所起到的显著作用，但大导通能力特性有所牺牲，存在进一步改善的潜力；（2）改进型PA区阳极高速LIGBT器件，包括槽型工艺新结构（TNCA-LIGBT）、埋层新结构（BNCA-LIGBT）和分离阳极新结构（SNCA-LIGBT）等三种器件，是对导通压降增大的NCA-LIGBT器件的进一步优化；（3）增强型PA区阳极高速LIGBT器件（ENCA-LIGBT），其PA区的形成利用了绝缘介质层结构，同时具有阳极掩蔽层的注入增强效应和非平衡载流子的抽出效应；（4）耗尽型PA区阳极高速LIGBT器件（DNCA-LIGBT），其电势控制PA区在器件的制造过程中由SOI底片的P-区自动形成，工作中处于耗尽状态，简化了工艺步骤，增强了电势控制能力。第三、提出三维电势控制高速LIGBT器件。通过电势控制抽出结构的三维设计同时减小电势控制因子r和三维调节因子K的取值，该类新结构包括：（1）分段PA区阳极高速LIGBT器件（Seg-NCA-LIGBT），利用电势控制PA区概念和抽出结构的三维设计实现了低导通特性和高速关断特性之间的方便选择；（2）双通道三维PA区阳极高速LIGBT器件（NPN-NCA-LIGBT），将电势控制PA区概念、部分NPN控制阳极概念和抽出结构的三维设计结合在一起，实现了关断态非平衡载流子的直接导通模式和NPN反向注入模式的双通道抽出机制；（3）复合PA区阳极高速LIGBT器件，包括常规型复合阳极新结构（Split-NCA-LIGBT）和透明型复合阳极新结构（Split-Striped-NCA-LIGBT）两种器件，复合阳极设计使阳极结构分为相互独立又彼此联系的两部分，弱化了导通态特性和关断态特性之间的制约关系。高速LIGBT电势控制理论及其新结构不仅适用于SOI技术的LIGBT，也适用于体硅基和其它半导体材料的LIGBT、纵向结构IGBT和高速Diode等其它电导调制型半导体功率器件。更多还原

【Abstract】 Widely used in all kinds of power electronics systems, IGBT（Insulated GateBipolar Transistor）, which has some advantages, such as low driving power dissipation,high current holding capability, good thermal stability, high breakdown voltage andlarge SOA （Safe Operating Area）, and which can be fabricated as discrete device or beintegrated to silicon-based and SOI-based （Silicon-On-Insulator-based） power IC（Integrated Circuit）, is a typical structure of the new semiconductor power devices withconductivity modulation effect characteristics. The conductivity modulation effectpermits IGBT to have a low on-state voltage drop （von）, but due to the removal of storedelectron-hole plasma in drift region, which is strongly dependent on the recombinationprocess of electron-hole pairs during turn-off period, it cause the turn-off time （toff）longer than that of MOSFET （Metal-Oxide-Semiconductor Field Effect Transistor）,which conducts by majority carrier during on and turn-off states. Long turn-off time,which limits the working frequency and make large turn-off power dissipation, is thebiggest barrier for further applications of IGBT. Finding new theory and new method ofaccelerating turn-off speed, improving the constraint relation of vonand toffis the basicquestion needing better solving.In this thesis, aiming at the basic constraint relation, with high speed Lateral IGBTon SOI substrate （SOI LIGBT） as the object of study, adopting the associative methodsof potential-adjusted analysis of the turn point from unipolar mode to bipolar mode,numerical simulation and experimentation, the new theory and the new device structuresare researched. A new theory, named Potential-Adjusted （PA） theory of high speedLateral IGBT, is proposed. Based on PA technology, two kinds of novel devices （highspeed LIGBTs with potential adjusting and3-D potential adjusting） are reported. Maininnovations of the research include:1. Potential-Adjusted （PA） theory of high speed Lateral IGBT is proposed. Theconcept of PA region, created by PA technology, is used to adjust the potentialdistribution of built-in reverse diode structure during on state, and to form an effective extracting path for excess carriers during turn-off state, which improves the electriccharacteristics of on state and turn-off state. This permits the device havenon-oscillation turning-on characteristics, high current holding capability，and highturn-off speed. For the PA technology and the new devices, to improve the constraintrelation of vonand toff, increasing the potential difference of the part located in anoderegion of the reverse diode structure is the common method to reduce the anode voltage(V_sb) of turn point from unipolar mode to bipolar mode, which eliminates snapbackphenomenon in I-V characteristics and increases conducting current during on state, andto form an effective extracting path for excess carriers, which accelerates the turn-offspeed during turn-off state. The expression of V_sb=（1+K·r）V0（IEEE Electron DeviceLetters, May,2010）, providing the relation of anode voltage of turn point （Vsb） and holeinjecting voltage （V₀,0.7V for silicon）, gives the way to design new high speed LIGBTbased on PA technology, which is reducing the potential adjusting factor （r） or3-Dadjusting factor （K）. Eliminating snapback phenomenon and handling high current, atypical new structure, named NPN-NCA-LIGBT, make the anode voltage of turn pointfall to about Vsb=1.1V; and the ratios of turn-off times for the NPN-NCA-LIGBTcomparing to that of SA-NPN-LIGBT and conventional LIGBT are1:1.57and1:35.58,respectively.2. Based on PA technology, high speed LIGBTs with potential adjusting are firstlypresented. Increasing the potential difference of PA region is used to reduce the potentialadjusting factor （r）, these novel structures include:（1） high speed LIGBT withnormalized PA region anode （NCA-LIGBT）, it shows the prominent effect of thecreative concept of PA region in designing high speed LIGBT, but its high currentholding capability is sacrificed somewhat;（2） high speed LIGBTs with improved PAregion anode, including LIGBT with trench PA region anode （TNCA-LIGBT）, LIGBTwith buried PA region anode （BNCA-LIGBT） and LIGBT with separated PA regionanode （SNCA-LIGBT）, which are the improved structures of NCA-LIGBT;（3） highspeed LIGBT with enhanced PA region anode （ENCA-LIGBT）, the forming of PAregion is used by isolative layer, and the device has both advantages of enhancedconductivity modulation effect and potential-adjusted electron extracting path;（4） highspeed LIGBT with depleted PA region anode （DNCA-LIGBT）, the forming of PA regionis used by P-region of SOI wafer, and it is depleted during operation, the process flow is simplified and the capability of potential adjusting is enhanced.3. Based on PA technology, high speed LIGBTs with3-D potential adjusting arereported. The3-D design of potential adjusted extracting structure are used to reduceboth the potential adjusting factor （r） and3-D adjusting factor （K）, these novelstructures include:（1） high speed LIGBT with segmented PA region anode（Seg-NCA-LIGBT）, due to the concept of PA region and the3-D design of extractingstructure, it has the free selection between high current and high speed;（2） high speedLIGBT with dual extracting paths3-D PA region anode （NPN-NCA-LIGBT）, due to theconcepts of PA region, NPN controlled and3-D design of extracting structure used foranode, it has two extracting paths for excess carriers during turn-off state, one is directconducting mode, and another is NPN reverse injecting mode;（3） high speed LIGBTswith split PA region anode, including LIGBT with normalized split PA region anode（Split-NCA-LIGBT） and LIGBT with striped split PA region anode（Split-Striped-NCA-LIGBT）, split anode concept makes the anode split to independentbut coupled two parts, which eases up the constraint relation of on state and turn-offstate characteristics.The Potential-Adjusted （PA） theory of high speed Lateral IGBT and the newstructures are not only used for LIGBT on SOI substrates, but also used for othersemiconductor power devices with conductivity modulation effect characteristics, suchas silicon and other materials LIGBT, vertical IGBT, high speed diodes and so on.更多还原