Electrical effects of dislocations and other crystallographic defects in Hg0.78Cd0.22Te n-on-p photodiodes

An understanding of the effects of dislocations in HgCdTe diodes is complicated by several issues such as the diode architecture, diode formation process, and the thermal history and location of the dislocations. To help decouple the effects of these factors, high stress films were used to lithographically introduce dislocations with different densities and locations during the fabrication process of ion implanted, n-on-p diodes. Both array and diode test structures were studied. After fabrication, the diodes were characterized with variable temperature I–V measurements and noise measurements. The diodes were then stripped and defect etched to quantify the density and distribution of the dislocations. The effects of these process-induced dislocations were analyzed and compared to the effects of as grown dislocations, subgrain boundaries and dislocations in other device architectures reported in the literature.^1,2 In general, high densities of either as grown or process-induced dislocations in n-on-p, ion implanted diodes severely degrade device performance by producing field dependent dark current At 77K, dislocation densities greater than the mid 10⁶ cm⁻² can produce dark current densities in excess of the diode diffusion current. Dislocations located near the outer periphery of the diode produce approximately ten times the dark current of interior dislocations. Grain boundaries, sub-grain boundaries, and twins also produce sufficient field dependent dark current to limit diode performance at 77K. The dark current produced by dislocations is nearly temperature in dependent, suggesting rather severe limitations on dislocation densities for low temperature diode operation.     

单片集成的低暗电流1.3 μm激光二极管和探测器芯片

为了在单片上实现半导体激光二极管与探测器的集成,开展了外延材料生长及结构工艺的设计研究。通过刻蚀工艺引入隔离区的方法制备了集成背光探测器的1.3m InGaAsP/InP半导体激光二极管芯片。管芯的光电性能测试显示,激光二极管具有较低的阈值电流17.62 mA,较高的斜率效率0.13 mW/mA,输出功率可达11 mW;在-0.7 V的反向偏压下,探测器区域对光信号具有良好的线性响应,MPD的光电流超过0.3 mA,在-1.7 V的反向偏压下,暗电流可低至25 nA。     

Design on the low-leakage diode string for using in the power-railESD clamp circuits in a 0.35-μm silicide CMOS process

A new design of the diode string with very low leakage current is proposed for use in the ESD clamp circuits across the power rails. By adding an NMOS-controlled lateral SCR (NCLSCR) device into the stacked diode string, the leakage current of this new diode string with six stacked diodes at 5 V (3.3 V) forward bias can be reduced to only 2.1 (1.07) nA at a temperature of 125°C in a 0.35 μm silicide CMOS process, whereas the previous designs have a leakage current in the order of mA. The total blocking voltage of this new design with NCLSCR can be linearly adjusted by changing the number of the stacked diodes in the diode string without causing latch-up danger across the power rails. From the experimental results, the human-body-model ESD level of the ESD clamp circuit with the proposed low-leakage diode string is greater than 8 kV in a 0.35 μm silicide CMOS process by using neither ESD implantation nor the silicide-blocking process modifications     

Performance evaluation of a Schottky SiC power diode in a boost PFC application

The performance of a 600 V, 4 A silicon carbide (SiC) Schottky diode (Infineon SDP04S60) is experimentally evaluated. A 300 W boost power factor corrector (PFC) with average current mode control is considered as a key application. Measurements of overall efficiency, switch and diode losses, and conducted electromagnetic interference (EMI) are performed both with the SiC diode and with two ultra-fast, soft-recovery, silicon power diodes, namely the RURD460 and the presented STTH5R06D. The paper compares the results to quantify the impact of the recovery current reduction provided by SiC diode on these key aspects of the converter behavior. Based on the experimental results, the paper shows that the use of SiC diodes in PFC designs may only be justified in high switching frequency applications.     

Comparison of current-voltage characteristics of n- and p-type 6H-SiC Schottky diodes

Current-voltage (I–V) characteristics of n- and p-type 6H−SiC Schottky diodes are compared in a temperature range of room temperature to 400°C. While the room temperature I–V characteristics of the n-type Schottky diode after turn-on is more or less linear up to ∼100 A/cm², the I–V characteristics of the p-type Schottky diode shows a non-linear behavior even after turn-on, indicating a variation in the on-state resistance with increase in forward current. For the first time it is shown that at high current densities (>125 A/cm²) the forward voltage drop across p-type Schottky diodes is lower than that across n-type Schottky diodes on 6H−SiC. High temperature measurements indicate that while the on-state resistance of n-type Schottky diodes increases with increase in temperature, the on-state resistance of p-type Schottky diodes decreases with increase in temperature up to ∼330 K.     

Development of large-area 200-volt planar voltage-variable capacitance diodes

A research and development program resulted in fabrication of high-capacitance voltage-variable capacitance diodes for electronic tuning. Devices were fabricated by epitaxial and planar technology, with the diode prepared by diffusion into n-type silicon to approximate an abrupt junction. Objective specifications required devices with capacitance of 250 pF and 1000 pF (-8V), breakdown voltageV_{(BR)} > 200V, capacitance change ratio of > 5.6 (-4 to -200 V), and quality factorQ > 200(10 MHz). The principal problem was theV_{(BR)}limitation of planar diodes, which results in part from the tendency of thermally oxidized n-type Si to form an accumulation layer in the Si at the Si-SiO2interface. The planar process was refined to achieve large-area 200-V planar diodes, while maintaining the other essential diode characteristics, by the introduction of modifications to lower the electrical field of the p-n junction at the surface. Both structural modifications and processing changes were found to result in an increase in the level ofV_{(BR)}of planar diodes.     

Silicon carbide PiN and merged PiN Schottky power diode models implemented in the Saber circuit simulator

Dynamic electrothermal circuit simulator models are developed for silicon carbide power diodes. The models accurately describe the temperature dependence of on-state characteristics and reverse-recovery switching waveforms. The models are verified for the temperature dependence of the on-state characteristics, and the di/dt, dv/dt, and temperature dependence of the reverse-recovery characteristics. The model results are presented for 1500 V SiC Merged PiN Schottky (MPS) diodes, 600 V Schottky diodes, and 5000 V SiC PiN diodes. The devices studied have current ratings from 0.25 A to 5 A and have different lifetimes resulting in different switching energy versus on-state voltage trade-offs. The devices are characterized using a previously reported test system specifically designed to emulate a wide range of application conditions by independently controlling the applied diode voltage, forward diode current, di/dt, and dv/dt at turn-off. A behavioral model of the test system is implemented to simulate and validate the models. The models are validated for a wide range of application conditions for which the diode could be used.     

SiC power diodes provide breakthrough performance for a wide rangeof applications

The electrical performance of silicon carbide (SiC) power diodes is evaluated and compared to that of commercially available silicon (Si) diodes in the voltage range from 600 V through 5000 V. The comparisons include the on-state characteristics, the reverse recovery characteristics, and power converter efficiency and electromagnetic interference (EMI). It is shown that a newly developed 1500-V SiC merged PiN Schottky (MPS) diode has significant performance advantages over Si diodes optimized for various voltages in the range of 600 V through 1500 V. It is also shown that a newly developed 5000 V SiC PiN diode has significant performance advantages over Si diodes optimized for various voltages in the range of 2000 V through 5000 V. In a test case power converter, replacing the best 600 V Si diodes available with the 1500 V SiC MPS diode results in an increase of power supply efficiency from 82% to 88% for switching at 186 kHz, and a reduction in EMI emissions     

SiC/Si heterojunction diodes fabricated by self-selective and byblanket rapid thermal chemical vapor deposition

SiC/Si heterojunction diodes have been fabricated by two different rapid thermal chemical vapor deposition (RTCVD) processes: a localized self-selective growth and blanket growth. The self-selective growth of crystalline cubic (β) SiC was obtained by propane carbonization of the Si substrate in regions unprotected by an SiO₂ layer, producing planar diodes. Mesa diodes were fabricated using the blanket growth of polycrystalline β-SiC produced by the decomposition of methylsilane (CH₃SiH₃). The SiC/Si heterojunction diodes show good rectifying properties for both device structures. Reverse breakdown voltage of 50 V was obtained with the self-selective SiC/Si diode. The mesa diodes exhibited even higher breakdown voltages (V_br) of 150 V and excellent ideality factors of 1.06 at 25°C. The high V_br and good forward rectifying characteristics indicate that the SiC/Si heterojunction diode represents a promising approach for the fabrication of wide-gap emitter SiC/Si heterojunction bipolar transistors     

单片集成式氮化镓基发光二极管的设计与制造

We report a new monolithic structure of GaN-based light-emitting diode(LED) which can be operated under high voltage or alternative current. Differing from the conventional single LED chip, the monolithic lightemitting diode(MLED) array contains microchips which are interconnected in series or parallel. The key chip fabrication processing methods of the monolithic LED array include deep dry etching, sidewall insulated protection, and electrode interconnection. A 12 V GaN-based blue high voltage light emitting diode was designed and fabricated in our experiment. The forward current-voltage characteristics of MLEDs were consistent with those of conventional single junction light emitting diodes.     

Low-voltage MOBILE logic module based on Si/SiGe interbandtunnelling diodes

Si/SiGe interband tunnelling diodes have been grown by MBE on high resistivity (n^-) silicon substrates. The device enables a very low voltage, high-speed logic on a silicon substrate. A novel self-aligned diode is processed using optical lithography and dopant-selective wet chemical etching. A maximum speed index for a 60 μm² anode area device is evaluated to 2.2 ns/V resulting in a switching speed of 0.5 ns. A logic latch built of two series connected diodes (MOBILE principle) is demonstrated, showing very robust logic operation at a supply voltage as low as 0.3 V. The used technology may be employed for a co-integration with both SiGe heterostructure bipolar- and field-effect transistor technology and may contribute to future low-voltage high speed logic on Si substrates     

SiGeC异质结功率二极管通态特性研究

研究了一种大功率低功耗p+(SiGeC)-n--n+异质结二极管结构,分析了Ge、C含量对器件正向通态特性的影响。结果表明:与常规的Si p-i-n二极管相比,在正向电流密度不超过1000 A/cm2情况下,p+(SiGeC)-n--n+二极管的正向压降有明显的降低。当电流密度为10 A/cm2时,Si p-i-n二极管的压降为0.655 V,而SiGeC异质结二极管的压降只有0.525 V,大大降低了器件的通态功耗。在相同正向电流密度的条件下,SiGeC异质结二极管在n-区存储的载流子比Si二极管的减少了1个数量级以上,这导致前者的关断时间远小于后者。     

Millimeter-wave diode-grid phase shifters

Monolithic diode grids have been fabricated on 2-cm square gallium-arsenide wafers with 1600 Schottky-barrier varactor diodes. Shorted diodes are detected with a liquid-crystal technique, and the bad diodes are removed with an ultrasonic probe. A small-aperture reflectometer that uses wavefront division interference was developed to measure the reflection coefficient of the grids. A Phase shift of 70° with a 7-dB loss was obtained at 93 GHz when the bias on the diode grid was changed from -3 V to 1 V. A simple transmission-line grid model, together with the measured low-frequency parameters for the diodes, was shown to predict the measured performance over the entire capacitive bias range of the diodes, as well as over the complete reactive tuning range provided by a reflector behind the grid, and over a wide range of frequencies form 33 GHz to 141 GHz. This shows that the transmission-line model and the measured low-frequency diode parameters can be used to design an electronic beam-steering array and to predict its performance. An electronic beam-steering array made of a pair of grids using state-of-the-art diodes with 5-Ω series resistances would have a loss of 1.4 dB at 90 GHz     

用于高功率密度功率因素校正的新一代600V砷化镓肖特基二极管

在200W连续导通模式功率因数校正（PFC）系统中，新一代600V砷化镓（GaAs）肖特基二极管与硅和碳化硅（SiC）二级管比较，砷化镓、碳化硅在PFC系统中的损耗减少高达25％。由于砷化镓有较低的结电容，砷化镓相对碳化硅高的通态损耗被较低的MOSFET损耗弥补了。和碳化硅技术相比，砷化镓有成本和可靠性优势。对于高频和高密度应用来说，新一代的砷化镓二级管是很有前景的。     

超结硅锗功率二极管电学特性的研究

超结SiGe功率开关二极管可以克服常规Si功率二极管存在的一些缺陷,如阻断电压增大的同时,正向导通压降也将增大,反向恢复时间也变长。该新型功率二极管有两个重要特点:一是由轻掺杂的p型柱和n型柱相互交替形成超结结构,代替传统功率二极管的n-基区;二是p+区采用很薄的应变SiGe材料。该器件可以同时实现高阻断电压、低正向压降和快速恢复的电学特性。与相同器件厚度的常规Si功率二极管相比较,反向阻断电压提高了42%,反向恢复时间缩短了40%,正向压降减小了约0.1V(正向电流密度为100A/cm2时)。应变SiGe层中Ge含量和器件的基区厚度是影响超结SiGe二极管电学特性的重要参数,详细分析了该材料参数和结构参数对正向导通特性、反向阻断特性和反向恢复特性的影响,为器件结构设计提供了实用的参考价值。     

Electrostatic Reliability Characteristics of GaN Flip-Chip Power Light-Emitting Diodes With Metal–Oxide–Silicon Submount

The electrostatic reliability characteristics of gallium nitride flip-chip (FC) power light-emitting diodes (PLEDs) with metal-oxide-silicon (MOS) submount are investigated for the first time. The electrostatic damage reliability of the reported diode submount and that of our proposed simple structure MOS submount are fabricated and compared. Their corresponding electrostatic protection capabilities are increased from 200 V (conventional PLED) to 500 V (FC-PLED on diode submount), to 500 V (FC-PLED on MOS submount with a SiO₂ thickness of 297 A?), and even to a value as high as 1000 V (FC-PLED at a SiO₂ thickness of 167 A?), which are much higher than the PLED industrial test value of 150 V at -5 V/-10 ? A criterion and are also much more robust than the previous academic reports.     

MIM薄膜二极管Ta_2O_5绝缘膜的AFM分析及其I-V特性研究

制备了一种用于有源矩阵液晶显示的Ｔａ－Ｔａ２Ｏ５－Ｔａ 结构ＭＩＭ 薄膜二极管。其中,作为介质层的Ｔａ２Ｏ５ 膜由不同成膜技术得到。采用原子力显微镜（ＡＦＭ）对Ｔａ２Ｏ５ 膜进行了表面形貌分析,并对其ＭＩＭ 二极管的伏安特性进行了测试与比较。结果表明,用溅射／阳极氧化二步法制备的Ｔａ２Ｏ５ 膜作绝缘层的ＭＩＭ 二极管,其Ｉ－Ｖ特性的非线性系数β＝ ２５,远高于阳极氧化法及溅射法所得Ｔａ２Ｏ５ 膜的ＭＩＭ 二极管的非线性系数（β＝ ９和５）,电流通断比（１０５）分别较阳极氧化法及溅射法工艺制备的ＭＩＭ－ＴＦＤ高１和３ 个数量级,且其伏安特性的对称性也较好     

Planar, ion implanted, high voltage 6H-SiC P-N junction diodes

Planar, high voltage (800 V) P-N junction diodes have been fabricated for the first time on N-type 6H-SiC by room temperature boron implantation through a pad oxide deposited within windows etched in an LPCVD field oxide. All the diodes showed excellent rectification with leakage currents of less than 10 nA (~5×10^-5 A/cm² ) until avalanche breakdown. It was found that the breakdown voltage increases with junction depth. The reverse recovery time (t_rr) was measured to be 50 ns for the 800 V diode from which an effective minority carrier life time of 12.5 ns was extracted     

一种带P型埋层的4H-SiC PiN二极管

碳化硅(SiC)PiN二极管是应用在高压大功率整流领域中的一种重要的功率二极管。受SiC外延材料的载流子寿命限制以及常规SiC PiN二极管较低的阳极注入效率的影响,SiC PiN二极管的正向导通性能较差,这极大限制了其在高压大电流领域的应用。文章提出了一种带P型埋层的4H-SiC PiN二极管,较常规SiC PiN二极管增强了阳极区的少子注入效率,降低了器件的导通电阻,增大了正向电流。仿真结果表明,当正向偏压为5 V时,引入P型埋层的SiC PiN二极管的正向电流密度比常规SiC PiN二极管提升了52.8%。     

Nanoantenna with Geometric Diode for Energy Harvesting

A graphene based geometrical diodes coupled with nanoantennas for infrared (IR) energy harvesting has been introduced. The geometrical diode is an electronic device in which the current flow through it is controlled by its geometry. The I–V characteristics of the graphene based geometrical diodes are calculated by the Monte Carlo simulation. Different shapes of graphene geometrical diodes, arrowhead, modified staircase, and quarter-elliptical geometries have been examined. The equivalent impedance, capacitance, and responsitivity of each geometric diode have been calculated. The radiation characteristics of nanoantenna designed at 20.5 THz have been investigated. The IR harvesting using nanoantenna coupled with the graphene geometric diode has been calculated and interpreted. Full-wave simulation for the nanoantenna coupled to the geometric diode has been introduced. The DC voltage collected by the nanoantenna and rectified using the geometrical diode has been calculated.