一种低功耗4H-SiC IGBT的仿真研究

针对传统沟槽栅4H-SiC IGBT关断时间长且关断能量损耗高的问题,文中利用Silvaco TCAD设计并仿真了一种新型沟槽栅4H-SiC IGBT结构。通过在传统沟槽栅4H-SiC IGBT结构基础上进行改进,在N ⁺缓冲层中引入两组高掺杂浓度P区和N区,提高了N ⁺缓冲层施主浓度,折中了器件正向压降与关断能量损耗。在器件关断过程中,N ⁺缓冲层中处于反向偏置状态的PN结对N ^-漂移区中电场分布起到优化作用,加速了N ^-漂移区中电子抽取,在缩短器件关断时间和降低关断能量损耗的同时提升了击穿电压。Silvaco TCAD仿真结果显示,新型沟槽栅4H-SiC IGBT击穿电压为16 kV,在15 kV的耐压设计指标下,关断能量损耗低至4.63 mJ,相比传统结构降低了40.41%。     

具有P型浮空区的槽栅IGBT结构

本文提出了一种具有P型浮空层的新型槽栅IGBT结构,它是在之前所提的一种积累层沟道控制的槽栅IGBT(TAC-IGBT)基础之上引入了一浮空P型层。此结构在维持原有TAC-IGBT低的正向导通压降和更大正向偏置安全工作区（FBSOA）的同时,减小了器件的泄漏电流,提高了器件的击穿电压,也使得器件的短路安全工作区大大提高,且制造简单,设计裕度增大。仿真结果表明：对于1200V的IGBT器件,具有P型浮空层的新型槽栅IGBT结构漏电比TAC-IGBT小近一个量级,击穿电压提高近150V。     

Trench gate IGBT structure with floating P region

A new trench gate IGBT structure with a floating P region is proposed,which introduces a floating P region into the trench accumulation layer controlled IGBT(TAC-IGBT).The new structure maintains a low on-state voltage drop and large forward biased safe operating area(FBSOA)of the TAC-IGBT structure while reduces the leakage current and improves the breakdown voltage.In addition,it enlarges the short circuit safe operating area(SCSOA)of the TAC-IGBT,and is simple in fabrication and design.Simulation results indicate that,for IGBT structures with a breakdown voltage of 1200 V, the leakage current of the new trench gate IGBT structure is one order of magnitude lower than the TAC-IGBT structure and the breakdown voltage is 150 V higher than the TAC-IGBT.     

Trench SJ IGBT 的仿真研究

本文对沟槽型超结绝缘栅双极晶体管(trench SJ IGBT)进行了全面的分析,并通过Sentaurus TCAD仿真软件将其与沟槽型场截止绝缘栅双极晶体管(trench FS IGBT)进行了详尽的对比,仿真结果显示,在相同的条件下与trench FS IGBT 相比,trench SJ IGBT 的击穿电压提高了100 V,饱和导通压降降低了0.2 V,关断损耗减少了50%。最后,文章研究了电荷不平衡对trench SJ IGBT 的动静态参数的影响。对各参数和它们对电荷不平衡的灵敏度之间的折中进行了讨论。     

具有积累层沟道的槽栅IGBT结构

提出了一种具有积累层沟道的槽栅IGBT结构。仿真结果表明：在阻断电压为1200V,集电极电流密度为100 A/cm2,温度分别为300K和400K下的情况下,积累层沟道槽栅IGBT的正向压降分别为1.5V 和2V而常规槽栅IGBT分别为1.7V和2.4V。新结构比常规槽栅IGBT具有更低的开态压降和更大的正向安全工作区。文中同时分析了积累层沟道槽栅IGBT的阻断特性和关断特性。     

Insulated gate bipolar transistor with trench gate structure of accumulation channel

An accumulation channel trench gate insulated gate bipolar transistor (ACT-IGBT) is proposed. The simu-lation results show that for a blocking capability of 1200 V, the on-state voltage drops of ACT-IGBT are 1.5 and 2 V at a temperature of 300 and 400 K, respectively, at a collector current density of 100 A/cm~2. In contrast, the on-state voltage drops of a conventional trench gate IGBT (CT-IGBT) are 1.7 and 2.4 V at a temperature of 300 and 400 K,respectively. Compared to the CT-IGBT, the ACT-IGBT has a lower on-state voltage drop and a larger forward bias safe operating area. Meanwhile, the forward blocking characteristics and turn-off performance of the ACT-IGBT are also analyzed.     

3300V沟槽栅IGBT的衬底材料的优化设计

使用TCAD仿真软件对3 300 V沟槽栅IGBT的静态特性进行了仿真设计.重点研究了衬底材料参数、沟槽结构对器件击穿电压、电场峰值等参数的影响.仿真结果表明,随衬底电阻率增加,击穿电压增加,饱和电压和拐角位置电场峰值无明显变化;随衬底厚度增加,击穿电压增加,饱和电压增加,拐角位置电场峰值降低;随沟槽宽度增加,饱和电压降低,击穿电压和拐角位置电场峰值无明显变化;随沟槽深度增加,饱和电压降低,击穿电压无明显变化,拐角位置电场峰值增加;随沟槽拐角位置半径增加,击穿电压和饱和电压无明显变化,但拐角位置电场峰值减小.选择合适的衬底材料对仿真结果进行实验验证,实验结果与仿真结果相符,制备的IGBT芯片击穿电压为4 128 V,饱和电压约为2.18 V.     

Ultra-low specific on-resistance SOI double-gate trench-type MOSFET

An ultra-low specific on-resistance(R_on,sp) silicon-on-insulator（SOI） double-gate trench-type MOSFET （DG trench MOSFET） is proposed.The MOSFET features double gates and an oxide trench:the oxide trench is in the drift region,one trench gate is inset in the oxide trench and one trench gate is extended into the buried oxide.Firstly,the double gates reduce R_on,sp by forming dual conduction channels.Secondly,the oxide trench not only folds the drift region,but also modulates the electric field,thereby reducing device pitch and increasing the breakdown voltage（BV）.A BV of 93 V and a R_on,sp of 51.8 mΩ·mm² is obtained for a DG trench MOSFET with a 3μm half-cell pitch.Compared with a single-gate SOI MOSFET（SG MOSFET） and a single-gate SOI MOSFET with an oxide trench（SG trench MOSFET）,the R_on,sp of the DG trench MOSFET decreases by 63.3%and 33.8% at the same BV,respectively.     

High-voltage accumulation-layer UMOSFET's in 4H-SiC

A novel silicon carbide UMOSFET structure is reported. This device incorporates two new features: a self-aligned p-type implantation in the bottom of the trench that reduces the electric field in the trench oxide, and an n-type epilayer under the p-base to promote lateral current spreading into the drift region. This UMOS structure is capable of supporting the full blocking voltage of the pn junction while keeping the electric field in the gate oxide below 4 MV/cm. An accumulation channel is formed on the sidewalls of the trench by epigrowth, and the gate oxide is produced by a polysilicon oxidation process, resulting in a uniform oxide thickness over both the sidewalls and bottom of the trench. The fabricated 4H-SiC devices have a blocking voltage of 1400 V (10 μm drift region), a specific on-resistance of 15.7 mΩ-cm ² at room temperature, and a gate oxide field of 3 MV/cm     

具有栅介质电场屏蔽作用的新型GaN纵向槽栅MOSFET器件设计

基于氮化镓(GaN)等宽禁带(WBG)半导体的金氧半场效应晶体管(MOSFET)器件在关态耐压下,栅介质中存在与宽禁带半导体临界击穿电场相当的大电场,致使栅介质在长期可靠性方面受到挑战。为了避免在GaN器件中使用尚不成熟的p型离子注入技术,提出了一种基于选择区域外延技术制备的新型GaN纵向槽栅MOSFET,可通过降低关态栅介质电场来提高栅介质可靠性。提出了关态下的耗尽区结电容空间电荷竞争模型,定性解释了栅介质电场p型屏蔽结构的结构参数对栅介质电场的影响规律及机理,并通过权衡器件性能与可靠性的关系,得到击穿电压为1 200 V、栅介质电场仅0.8 MV/cm的具有栅介质长期可靠性的新型GaN纵向槽栅MOSFET。     

Reverse‐Conducting IGBT Using MEMS Technology on the Wafer Back Side

In this paper, we present a 600‐V reverse conducting insulated gate bipolar transistor (RC‐IGBT) for soft and hard switching applications, such as general purpose inverters. The newly developed RC‐IGBT uses the deep reactive‐ion etching trench technology without the thin wafer process technology. Therefore, a freewheeling diode (FWD) is monolithically integrated in an IGBT chip. The proposed RC‐IGBT operates as an IGBT in forward conducting mode and as an FWD in reverse conducting mode. Also, to avoid the destructive failure of the gate oxide under the surge current and abnormal conditions, a protective Zener diode is successfully integrated in the gate electrode without compromising the operation performance of the IGBT.     

具有沟槽阳极短路的新型沟槽栅场截止绝缘栅双极晶体管

文章提出了一种新型的具有沟槽阳极短路的槽栅场截止型绝缘栅双极晶体管结构。通过引入沟槽短路阳极结构,器件的击穿电压得到了明显提高。仿真结果显示,相比于传统的场截止型绝缘栅双极晶体管,新结构提高了19.5 %的击穿电压,而且新结构具有更小的漏电流。在电流密度为150 A/cm2 时,新结构虽然提高了近百分之九的导通压降,但是关断时间只有传统结构的一半。此外,新结构导通时没有负阻效应。因此,新结构具有更好的关断功耗与导通压降的折中关系。     

A novel trench gate floating islands power MOSFET (TG-FLIMOSFET): Two-dimensional simulation study

Novel trench gate floating islands MOSFET (TG-FLIMOSFET) designed using the concept of “Opposite Doped Buried Regions” (ODBR) and floating islands (FLI) along with trench gate technology is proposed and verified using two-dimensional simulations. The conventional FLIMOSFET experimentally demonstrated recently, although offers lowest on-resistance in the low voltage range, however, suffers from quasi-saturation effect like any other power MOSFETs. The proposed TG-FLIMOSFET demonstrated to obtain about 30% reduction in peak electric field in drift region of the proposed device. TG-FLIMOSFET also demonstrates quasi-saturation free forward and transconductance characteristics, improved synchronous rectifying characteristics, identical breakdown voltage, reduced on-resistance and increased transconductance ‘gm’ when compared with the conventional FLIMOSFET for various trench geometries. The proposed device breaks the limit set by the conventional FLIMOSFET approximately by a factor of 10. A possible process flow sequence to fabricate the proposed device commercially by integrating multi-epitaxial process with trench gate technology is also presented.     

电子辐照对槽栅IGBT器件参数影响分析

功率器件IGBT由于其优异特性而广泛应用于电机、电焊机和功率开关等领域,是功率器件的主流产品之一。本文首先介绍了电子辐照技术在改善IGBT关断时间的应用,以及该技术在槽栅IGBT应用中出现的异常现象,并提出了改善此类异常现象的器件制造方法。     

A novel trench clustered insulated gate bipolar transistor (TCIGBT)

A new trench clustered insulated gate bipolar transistor (TCIGBT) is reported. In this device, a multitude of UMOS cathode cells is enclosed within a common n-well and p-well. The TCIGBT provides a unique "self-clamping" feature to protect the trenches from high electric fields. The simulation results based on 1.2 kV nonpunchthrough technology indicate an improvement of 25% in on state and 28% in the turn-off losses in comparison to the state-of-the-art trench IGBT. The saturation current levels of the TCIGBT, which can be designed independent of the forward drop, are also lower.     

A novel gate geometry for the IGBT: the trench planar insulatedgate bipolar transistor (TPIGBT)

This letter demonstrates a simple way to improve the performance of a planar, fine lithography insulated gate bipolar transistor (IGBT), by incorporating a trench gate between the cathode cells. The results of this new trench-planar IGBT (TPIGBT) clearly demonstrate a significant reduction in the voltage drop without degrading the breakdown voltage. The switching analysis indicates that the TPIGBT represents a good trade-off between planar and trench structures. By separating the trench gate requirements away from the cathode cells, the technology development cycle and costs can be reduced. Furthermore, the reduced cell-width and the shallow trench presents TPIGBT as a cost-effective structure for high-voltage applications     

用于工业的具有高频开关性能的1200V IGBT模块

带有平面门极和场止结构的新型IGBT器件已应用到最新研发的1200V模块上。与沟槽门极IGBT模块降低大约20%的功率损耗。     

高压Trench IGBT的研制

介绍了当前绝缘栅双极晶体管(IGBT)的几种结构及沟槽型IGBT的发展现况,分析了高电压沟槽型非穿通(NPT)IGBT的结构及工艺特点。通过理论分析计算出初步器件的相关参数,再利用ISE仿真软件模拟器件的结构及击穿和导通特性,结合现有沟槽型DMOS工艺流程,确定了器件采用多分压环加多晶场板的复合终端、条状元胞、6μm深度左右沟槽、低浓度背面掺杂分布与小于180μm厚度的器件结构,可以很好地平衡击穿特性与导通特性对器件结构的要求。成功研制出1 200 V沟槽型NPT系列产品,并通过可靠性考核,经过电磁炉应用电路实验,结果表明IGBT器件可稳定工作,满足应用要求。该设计可适合国内半导体生产线商业化生产。     

SiGe-collector trench gate insulated gate bipolar transistor fabricated using multiple target sputtering

A new type of trench gate IGBT (insulated gate bipolar transistor) which uses a SiGe layer for the collector is experimentally investigated. SiGe collectors with different Ge content are deposited by multiple cathode sputtering making low temperature processing possible. The change in turn-off characteristics with Ge content is also investigated. Results indicate that the use of a SiGe collector reduces the tail current at turn-off due to the reduced injection of holes to the n⁻ drift region.     

具有L型栅极场板的双槽双栅绝缘体上硅器件新结构

为了降低绝缘体上硅（SOI）功率器件的比导通电阻,同时提高击穿电压,利用场板（FP）技术,提出了一种具有L型栅极场板的双槽双栅SOI器件新结构.在双槽结构的基础上,在氧化槽中形成第二栅极,并延伸形成L型栅极场板.漂移区引入的氧化槽折叠了漂移区长度,提高了击穿电压;对称的双栅结构形成双导电沟道,加宽了电流纵向传输面积,使比导通电阻显著降低;L型场板对漂移区电场进行重塑,使漂移区浓度大幅度增加,比导通电阻进一步降低.仿真结果表明：在保证最高优值条件下,相比传统SOI结构,器件尺寸相同时,新结构的击穿电压提高了123%,比导通电阻降低了32%;击穿电压相同时,新结构的比导通电阻降低了87.5%;相比双槽SOI结构,器件尺寸相同时,新结构不仅保持了双槽结构的高压特性,而且比导通电阻降低了46%.