Analysis of a high-voltage merged p-i-n/Schottky (MPS) rectifier

A new operating mode for the merged p-i-n/Schottky (MPS) rectifier structure is analyzed. It is shown that these devices exhibit superior forward-drop and turn-off-speed characteristics. As an example, for the same forward drop, the 400-V MPS rectifier is an order of magnitude faster in switching speed when compared to a p-i-n rectifier. In addition, for equal switching speed, the MPS rectifier has much lower forward drop and leakage current.     

Rectifier characteristics based on bipolar-mode SIT operation

A novel rectifier concept based on bipolar-mode static induction transistor (BSIT) operation is proposed. A numerical simulation has revealed that the turn-on mechanism of this rectifier, owing to a combination of static induction effects and minority carrier injection, can make its forward-voltage drop and reverse recovery time smaller than those of the conventional p-i-n rectifier. As an example of the design methods, the simulation has clarified the effects of decreasing the doping concentration in the channel between p⁺ regions on improvement in the tradeoff between a forward voltage drop and leakage current     

超低漏电流超快恢复SiGeC功率二极管研究

 提出一种超低漏电流超快恢复SiGeC p-i-n二极管结构.基于异质结电流输运机制,该SiGeC二极管实现了低通态压降下高电流密度的传输,改善了二极管的反向恢复特性,同时具有较低的反向漏电流.与少子寿命控制技术相比,该器件有效协调了降低通态电压、减小反向漏电流、缩短反向恢复时间三者之间的矛盾.对不同温度下器件反向恢复特性研究结果表明,SiGeC二极管的反向恢复时间与同结构SiGe二极管相比,350K时缩短了1/3,400K时缩短了40%以上,器件的热稳定性显著提高,降低了对器件后续制作工艺的限制,有益于功率集成.     

多晶PIN二极管及二极管串作良好工艺兼容并可移植ESD保护器件的研究

作为静电保护保护器件,多晶PIN二极管具有良好工艺兼容性及可移植的优点。文章制作并展示了多晶PIN二极管的反向击穿电压、漏电流及电容特性,同时通过正向及反向传输线脉冲电流电压特性评估了其静电保护能力。另外为了经一部降低电容并控制反向崩溃及正向开启电压对多晶PIN二极管串进行了研究。最后对器件特性进行了分析讨论,阐明了器件参数对性能的影响。     

A new 4H-SiC lateral merged double Schottky (LMDS) rectifier withexcellent forward and reverse characteristics

The novel characteristics of a new Schottky rectifier structure, known as the lateral merged double Schottky (LMDS) rectifier, on 4H-SiC are explored theoretically and compared with those of the compatible conventional 4H-SiC Schottky rectifiers. The anode of the proposed lateral device utilizes the trenches filled with a high barrier Schottky (HBS) metal to pinch off a low barrier Schottky (LBS) contact during reverse bids. Numerical simulation of any such SiC structure is complicated by the fact that the thermionic emission theory predicts the reverse leakage current to be orders of magnitude smaller than the measured data. We, therefore, first propose a simple empirical model for barrier height lowering to accurately estimate the reverse leakage current in a SiC Schottky contact. The accuracy of the empirical model is verified by comparing the simulated reverse leakage current with the reported experimental results on different SiC Schottky structures. Using the proposed empirical model, the two-dimensional (2-D) numerical simulations reveal that the new LMDS rectifier demonstrates about three orders of magnitude reduction in the reverse leakage current and two times higher reverse breakdown voltage when compared to the conventional lateral low barrier Schottky (LLBS) rectifier while keeping the forward voltage drop comparable to that of the conventional LLBS rectifier     

不同退火处理的台面型In0.83Ga0.17As pin光电二极管暗电流分析

为了研究延伸波长In0.83Ga0.17As pin光电二极管的暗电流机制。采用两种不同工艺制备了台面型延伸波长In0.83Ga0.17As pin光电二极管。第一种工艺(M135L-5)是:台面刻蚀后进行快速热退火(RTA)。第二种工艺(M135L-3)是:台面刻蚀前进行快速热退火(RTA)。采用IV测试,周长面积比(P/A),激活能和暗电流成分拟合方法对器件暗电流机制进行分析。结果显示,在220~300 K之间,M135L-3器件暗电流低于M135L-5器件的,并且具有较低表面漏电流。在-0.01~-0.5 V之间和220~270 K之间,M135L-5器件的暗电流主要是扩散电流。在250~300 K之间,M135L-3器件的暗电流主要是扩散电流,而在-0.01~-0.5 V之间和220~240 K之间,其暗电流主要是产生复合电流和表面复合电流。与此同时,暗电流成分拟合结果也得出一致的结论。研究表明,在降低器件暗电流方面,M135L-3器件优于M135L-5器件,这主要是因为快速热退火降低了器件的体电流。     

Investigation of the polysilicon p-i-n diode and diode string as a process compatible and portable ESD protection device

正The polysilicon p-i-n diode displays noticeable process compatibility and portability in advanced technologies as an electrostatic-discharge(ESD) protection device.This paper presents the reverse breakdown,current leakage and capacitance characteristics of fabricated polysilicon p-i-n diodes.To evaluate the ESD robustness,the forward and reverse TLPⅠ-Ⅴcharacteristics were measured.The polysilicon p-i-n diode string was also investigated to further reduce capacitance and fulfill the requirements of tunable cut-in or reverse breakdown voltage. Finally,to explain the effects of the device parameters,we analyze and discuss the inherent properties of polysilicon p-i-n diodes.     

SiGeC/Si功率二极管的数值模拟与分析

将SiGeC技术应用于功率半导体器件的特性改进,提出了一种新型p (SiGeC)-n--n 异质结功率二极管结构.在分析SiGeC合金材料物理特性的基础上,给出了该结构的关键物理参数模型,并在此基础上利用MEDICI模拟,对比分析了C的引入对器件各种电特性的影响.此外,还模拟比较了不同p 区厚度对器件反向漏电流的影响.结果表明:在SiGe/Si功率二极管中加入少量的C,在基本不影响器件正向I-V特性和反向恢复特性的前提下,大大减少了器件的反向漏电流,并且C的加入还减小了器件特性对材料临界厚度的依赖性,提高了器件稳定性.     

A fully planarized 4H-SiC trench MOS barrier Schottky (TMBS)rectifier

A fully planarized 4H-SiC trench MOS barrier Schottky (TMBS) rectifier has been designed, fabricated and characterized for the first time. The use of a TMBS structure helps improve the reverse leakage current by more than three orders of magnitude compared to that of a planar Schottky rectifier. We have achieved a low reverse leakage current density of 6×10^-6 A/cm² and a low forward voltage drop of 1.75 V at 60 A/cm² for the TMBS rectifier. The static current-voltage (I-V) and switching characteristics of the TMBS rectifier have been measured at various temperatures. A barrier height of 1.0 eV and an ideality factor of 1.8 were extracted from the forward characteristics. The switching characteristics do not change with temperature indicating the essential absence of stored charge     

An Efficiency-Enhanced CMOS Rectifier With Unbalanced-Biased Comparators for Transcutaneous-Powered High-Current Implants

This paper presents an efficiency-enhanced integrated full-wave CMOS rectifier for the transcutaneous power transmission in high-current biomedical implants. The comparator-controlled switches are developed to minimize the voltage drop along the conducting path while achieving the unidirectional current flow. The proposed unbalanced-biasing scheme also minimizes the reverse leakage current of the rectifier under different input amplitudes, thereby optimizing the rectifier power efficiency. Moreover, the proposed rectifier is able to self start and operates at low input amplitudes.      

高温AlN为模板的AlGaN基p-i-n背照式日光盲探测器

第一次报道了以高温AlN为模板层的AlGaN基p-i-n背照式日光盲探测器的制作和器件特性.利用MOCVD方法在(0001)面的蓝宝石衬底上生长了探测器的AlxGa1-xN多层外延材料.在无需核化层的高温AlN模板上生长了p-i-n背照式日光盲探测器的无裂纹高Al组分(0.7)AlGaN多层外延结构.利用在线反射监测仪、三轴X射线衍射及原子力显微镜表征了外延材料的晶体质量.在1.8V的反向偏压下,制作的探测器表现出了日光盲响应特性,在270nm处最大响应度为0.0864A/W.具有约3.5V的正向开启电压,大于20V的反向击穿电压,在2V的反向偏压下暗电流小于20pA.     

高温AlN为模板的AlGaN基p-i-n背照式日光盲探测器

第一次报道了以高温AlN为模板层的AlGaN基p-i-n背照式日光盲探测器的制作和器件特性.利用MOCVD方法在(0001)面的蓝宝石衬底上生长了探测器的AlxGa1-xN多层外延材料.在无需核化层的高温AlN模板上生长了p-i-n背照式日光盲探测器的无裂纹高Al组分(0.7)AlGaN多层外延结构.利用在线反射监测仪、三轴X射线衍射及原子力显微镜表征了外延材料的晶体质量.在1.8V的反向偏压下,制作的探测器表现出了日光盲响应特性,在270nm处最大响应度为0.0864A/W.具有约3.5V的正向开启电压,大于20V的反向击穿电压,在2V的反向偏压下暗电流小于20pA.     

Reduction of leakage current of large-area high-resistivity silicon p-i-n photodiodes for detection at 1.06 µm

An experimental study has been carried out to reduce the leakage current of large-area (>2.5 cm²) high-resistivity (p-type, 8000 to 15 000 Ω . cm) fully depleted silicon p-i-n photodiodes. A new process technology, using low temperature oxidation and utilizing complete implantation doping, has been successfully developed. This process reproducibly gives photodiodes with generation-limited leakage current. The lowest level of leakage current achieved is in the order of 1 µA/cm³per unit depletion volume at 200-V reverse bias.     

ShOC rectifier: a new metal-semiconductor device with excellent forward and reverse characteristics

We report a new structure, called the shielded ohmic contact (ShOC) rectifier which utilizes trenches filled with a high-barrier metal to shield an Ohmic contact during the reverse bias. When the device is forward biased, the ohmic contact conducts with a low forward drop. However, when reverse biased, the Ohmic contact is completely shielded by the high-barrier Schottky contact resulting in a low reverse leakage current. Two dimensional numerical simulation is used to evaluate and explain the superior performance of the proposed ShOC rectifier.     

Cadmium sulfide passivation of InGaAs/InP mesa p-i-n photodiodes

A cadmium sulfide (CdS) passivation process was demonstrated for the first time on InGaAs/InP p-i-n mesa photodetectors. The passivated devices produced lower reverse bias leakage currents in comparison to devices that received only a thermally deposited SiO₂ film. The subsequent deposition of SiO₂ on the passivated devices produced virtually no change to the aforementioned leakage currents even after undergoing a 3-h, 300°C thermal treatment. In contrast, similar SiO₂ capped devices, fabricated without the CdS passivating layer, show a large increase in leakage current when subjected to the same thermal cycle. Leakage current versus mesa diameter measurements suggest these results are due to reduce surface recombination at the exposed mesa sidewall. X-ray photoelectron spectroscopy (XPS) results indicate the S:Cd ratio of these films to be 0.77.     

一种新型肖特基整流管设计

在研究功率肖特基整流管的基础上,针对反向击穿电压、漏电流、抗浪涌能力的提高,采取加场限环的方法,设计并制造了一种新型结势垒肖特基整流管(Junction barrier Schottky rectifier,JBS)。通过从有源区参数、外延材料、流片工艺、产品电参数、可靠性等方面进行了全面设计。经测试,电参数水平正向电压VF：0.85-0.856V,反向电流IR：4-50.5uA,反向电压VR:307.5-465.2V,抗静电水平从低温退火的6-12KV提高到15KV,经高温直流老化后,可靠性电参数水平满足预期的设计要求。     

Advanced High-Voltage 4H-SiC Schottky Rectifiers

This paper presents advanced 4H-SiC high-voltage Schottky rectifiers with improved performance when compared to conventional 4H-SiC Schottky rectifiers. Two types of 4H-SiC junction barrier Schottky (JBS) rectifiers have been explored. These rectifiers offer Schottky-like ON-state and fast switching characteristics, while their OFF-state characteristics have a low leakage current similar to that of the PiN junction rectifier. Planar 4H-SiC JBS rectifiers, with more than 1-kV blocking capability and orders of magnitude lower reverse leakage current than that of conventional SiC Schottky rectifiers, have been demonstrated. In addition, a novel device structure, called lateral channel JBS rectifier, was designed and experimentally demonstrated in 4H-SiC with up to 1.5-kV blocking capability and pinlike reverse characteristics.      

整流二极管的IR对HTRB工作寿命的影响

整流器件在工作中的可靠性往往与其漏电流特别是在高温下的漏电流有密切关系,然而对高温下的漏电流往往关注不够。通过对常温与高温漏电流的对比测试,发现两者并没有一致的对应关系;通过对高温漏电流有较大差别的两组样品的高温反偏寿命试验表明:高温漏电流越大,高温反偏寿命越短,说明高温漏电流对高温反偏寿命有重要影响。依据此结果提出了通过对高温漏电流进行测试,实现对高温反偏寿命进行分档、筛选的设想。介绍了利用正向脉冲电流对二极管的pn结进行瞬态加热以实现对高温反向漏电流的快速测试的具体方法。     

Analytical Modeling of High-Voltage 4H-SiC Junction Barrier Schottky (JBS) Rectifiers

We develop a new analytical model for the junction barrier Schottky (JBS) rectifier and apply it to high-voltage 4H-SiC JBS rectifiers. This model uses a novel method to approximate the electric field at the Schottky contact, which is together with the Fowler–Nordheim tunneling equation to accurately calculate the reverse leakage current of a high-voltage 4H-SiC JBS rectifier. The forward on-resistance of a high-voltage 4H-SiC JBS rectifier consists of several components, which are dominated by the spreading resistances in the drift layer. Moreover, this model has been verified by comparing the simulation and experimental results, and they are shown to be in good agreement.      

Complementary tunneling transistor for low power application

The metal oxide semiconductor field effect transistor (MOSFET) is scaling to a “tunneling epoch”, in which multiple leakage current induced by different tunneling effects exist. The complementary Si-based tunneling transistors are presented in this paper. The working principle of this device is investigated in detail. It is found that the band-to-band tunneling current is be controlled by the gate-to-source voltage. Due to the reverse biased p-i-n diode structure, an ultra-low leakage current is achieved. The sub-threshold swing of TFET is not limited by kt/q, which is the physical limit of the MOSFET. Using the CMOS compatible processes, the complementary TFETs (CTFET) are fabricated on one wafer. From a circuit point of view, the compatibility between TFET and MOSFET enables the transfer of CMOS circuits to CTFET circuits.