CCD输出二极管反向漏电机理的研究

分析了CCD输出二极管反向漏电的机理,认为有三个途径造成CCD反向漏电：n^ 区通过SiO2漏电,n^ 区通过Si-SiO2表面漏电以及体内漏电。提出了解决漏电问题的方法,即控制好氧化、扩散、离子注入、光刻以及退火等工艺。     

Si基JBS整流二极管的设计与制备

基于JBS整流二极管理论,详细介绍了一种Si基JBS整流二极管设计方法、制备工艺及测试结果。在传统肖特基二极管(SBD)有源区,利用光刻和固态源扩散工艺形成掺硼的蜂窝状结构,与n型衬底形成pn结,反向偏置时抑制了因电压增加引起的金属-半导体势垒高度降低,减小了漏电流;采用离子注入形成两道场限环的终端结构,有效防止了边缘击穿,提高了反向击穿电压。对制备的器件使用Tektronix 370B可编程特性曲线图示仪进行了I-V特性测试,结果表明本文设计的Si基JBS整流二极管正向压降VF=0.78 V(正向电流IF=5 A时),反向击穿电压可达340 V。     

Thermally-enhanced remote plasma nitrided ultrathin (1.65 nm) gateoxide with excellent performances in reduction of leakage current andboron diffusion

Ultrathin thermally enhanced remote plasma nitrided oxides (TE-RPNO) with equivalent oxide thickness down to 1.65 nm are fabricated to investigate their leakage current reduction and boron diffusion barrier performances. A PMOSFET with TE-RPNO, compared to its conventional oxide counter-part, yields almost one order magnitude lower gate leakage current, less flatband voltage changes in high boron implantation dose or activation temperature, and shows broader process windows in the tradeoff between boron penetration and dopant activation     

A novel self-aligned TiN formation by N2+implantation during two-step annealing Ti-salicidation for submicrometerCMOS technology application

A new technology of self-aligned TiN/TiSi₂ formation using N₂⁺ implantation during two-step annealing Ti-salicidation process has been developed. The formation of TiN was confirmed by RBS analysis. The leakage currents of n⁺/p junction diodes fabricated using this technology were measured to investigate the phenomena of Al spiking into Si-substrate. The measured reverse-bias leakage current of diode per unit junction area with Al/TiN/TiSi₂ contact is 1.2 nA/cm² at -5 V, which is less than all of reported data. Also it can sustain the annealing process for 30 min at 500°C. Thus, TiN formed with this technology process is suggested as a very effective barrier layer between TiSi₂ and Al for submicron CMOS technology applications     

Characteristics of polysilicon contacted shallow junction diodeformed with a stacked-amorphous-silicon film

A high-performance shallow junction diode formed with a stacked-amorphous-silicon (SAS) film is presented. Since the boundaries of stacked silicon layers and the poly/mono silicon interface act as a diffusion barrier for implanted dopants, the junction depth of SAS emitter contacted diode is about 500 Å shallower than that of the as-deposited polysilicon emitter contacted diode. The fabricated SAS emitter contacted diodes exhibited a very low reverse leakage current (⩽1 nA/cm² at -5 V) and a forward ideality factor m ≈1.001 over seven decades on a log scale. The reverse I-V characteristics were found to be nearly independent of the reverse voltage from room temperature to 200°C, and it was also found that the leakage current was due almost completely to the diffusion current. The plots of the diode leakage current versus the perimeter to area ratio showed that the periphery-generation current contributed little to the total leakage. The processing temperature for the SAS emitter contacted p⁺-n diode can be as low as 600°C     

Lifetime control in silicon power P-i-N diode by ion irradiation: Suppression of undesired leakage

The irradiation with high-energy (7.35 MeV) protons through a set of energy degraders was used to suppress leakage of the silicon power diodes subjected to local lifetime control. The aim was to modify the profile of recombination centers and to reduce production of vacancy complexes. The high-energy proton irradiation was compared with standard local lifetime killing by high-energy alphas. Recombination centers arising from irradiation were characterized after irradiation and subsequent annealing at 220 and 350 °C by deep level transient spectroscopy and I-V profiling. Static and dynamic parameters of irradiated diodes were also measured and compared. Results show that the applied irradiation with protons provides 3-10 times lower leakage compared to standard alphas for equivalent reduction of the reverse recovery current maximum. On the other hand, the excessive formation of hydrogen donors at high proton fluences and their diffusion during annealing at 350° decreases diode blocking capability.     

Advantages of LDD-only implanted fluorine with submicron CMOStechnologies

The effect of fluorine implantation on the properties of shallow n ⁺/p junctions has been investigated. The novel approach of this work lies in the introduction of fluorine only in the LDD regions of the device and not in the active region underneath the gate. Gated diodes were used as test vehicles to study the effect of the fluorine incorporation. Gated diodes are ideal for measurements of this nature since they are sensitive to changes in the interfacial properties near the gate to diffusion overlap region. Results from electrical device characterization indicate a reduction in gated diode leakage and mid-gap interface state density as the F-implanted dose is increased without causing any significant change in the flat-band voltages. Results also showed that samples with F incorporation tended to be more robust to electrical stress than those without F. Materials analysis indicated reduced junction depths for samples with F introduced in the LDD regions indicating suppression of phosphorus dopant diffusion     

Leakage current and defect characterization of pn-source/drain diodes

A good control of the transient enhanced dopant diffusion is needed for MOSFET scaling down to the sub 50 nm regime. Carbon ion implant is known to significantly suppress the transient enhanced boron diffusion. However, carbon implantation is also reported to increase diode leakage current. This paper investigates the impact of ion implantation and annealing conditions during source/drain extension formation on leakage current behavior of boron/phosphorous diodes of PFET transistors. Analyzing the leakage current it is difficult to distinguish between the influence of the increased electric field due to the reduced diffusion and possible additional trap centers in the space charge region. This distinction can be made by electrical characterization, as shown in this paper. The leakage current mechanism is found to be trap assisted tunneling with phonon interaction. The corresponding trap energy within the band gap is 0.58 ± 0.10 eV. The carbon concentration in the space charge region measured by SIMS is below the detection limit. Also in electrical measurements, which are more sensitive, no significant influence of carbon related traps is observed. The leakage current is increased by the application of a Flash Anneal additionally to a Rapid Thermal Anneal for recrystallization of the silicon substrate.     

Diode and MOSFET Properties of Trench‐Gate‐Type Super‐Barrier Rectifier with P‐Body Implantation Condition for Power System Application

In this paper, we investigate the electrical characteristics of two trench‐gate‐type super‐barrier rectifiers (TSBRs) under different p‐body implantation conditions (low and high). Also, design considerations for the TSBRs are discussed in this paper. The TSBRs’ electrical properties depend strongly on their respective p‐body implantation conditions. In the case of the TSBR with a low p‐body implantation condition, it exhibits MOSFET‐like properties, such as a low forward voltage (V_F) drop, high reverse leakage current, and a low peak reverse recovery current owing to a majority carrier operation. However, in the case of the TSBR with a high p‐body implantation condition, it exhibits pn junction diode–like properties, such as a high V_F, low reverse leakage current, and high peak reverse recovery current owing to a minority carrier operation. As a result, the TSBR with a low p‐body implantation condition is capable of operating as a MOSFET, and the TSBR with a high p‐body implantation condition is capable of operating as either a pn junction diode or a MOSFET, but not both at the same time.     

3 A/40 V新型肖特基势垒二极管的设计与研制

为提高传统肖特基二极管的击穿电压,减小了器件的漏电流,提高芯片利用率,文中设计研制了适合于裸片封装的新型肖特基势垒二极管(SBD)。利用Silvaco Tcad软件模拟,在器件之间采用PN结隔离,器件周围设计了离子注入形成的保护环,实现了在浓度和厚度分别为7.5×1012 cm-3和5 μm的外延层上,制作出了反向击穿电压45 V和正向导通压降0.45 V的3 A/45 V肖特基二极管,实验和仿真结果基本吻合。此外,还开发了改进SBD结构、提高其电特性的工艺流程。     

Increased radiative recombination of AlGaN-based deep ultraviolet laser diodes with convex quantum wells

An AlGaN-based deep ultraviolet laser diode with convex quantum wells structure is proposed. The advantage of using a convex quantum wells structure is that the radiation recombination is significantly improved. The improvement is attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes, which results in an increased hole injection efficiency and a decreased electron leakage into the p-type region. Particularly, comparisons with the convex quantum barriers structure and the reference structure show that the convex quantum wells structure has the best performance in all respects.     

Power bipolar transistors with a fast recovery integrated diode

We have integrated a fast recovery diode in the structure of a power bipolar transistor. This integral diode is physically connected between the emitter and the collector of the transistor and can be used as a free-wheeling diode in power switches. Selective reduction of the minority carrier lifetime in the region of the diode was realized by Pt implantation in the diode area followed by an optimized thermal process that limits the lateral diffusion of the metal atoms. Using this metal doping a reduction by a factor of 10 of the reverse recovery charges of the integrated diode is obtained without affecting significantly the current carrying capability of the transistor     

Enhancement in electrical properties of Au/n-GaAs Schottky diodes exposed to 60Co gamma rays

The effect of γ-ray exposure on the electrical characteristics of Au/n-GaAs Schottky barrier diodes has been investigated using current–voltage and capacitance–voltage techniques. The results indicate that irradiation with a cumulative dose of 10 Mrad (Si) improves the electrical characteristics of the diode. The parameters like ideality factor, series resistance and reverse leakage current determined from the current–voltage data decreases, whereas the barrier height and rectification ratio increases upon irradiation. The effective barrier height deduced from the capacitance–voltage technique has also increased with irradiation. The irradiated diode shows a higher carrier concentration compared to the virgin diode. The observed overall improvement in the diode quality is attributed to the annealing effect of γ-rays.     

Current transport in an ion-implanted diode

In a Schottky diode, the diode saturation current is controlled by the barrier height at the metal and semi-conductor contact, assuming that the dominant current is due to thermionic emission. When ion implantation is used to increase the barrier height, both thermionic emission and drift-diffusion of carriers become important in calculating the current. Numerical methods are used in solving Poisson's equation and the current continuity equations for an ion implanted doping profile. The electron and hole current in the surface region are calculated as a function of the total implantation dosage. The results show that the decrease of saturation current and the increase of effective barrier height in an ion implanted diode is mainly due to the suppression of the thermionic emission current by the implanted impurity atoms, rendering the diode to act like a pn junction.     

IMPATT oscillators with enhanced leakage current

The behavior of IMPATT oscillators with enhanced leakage current has been experimentally evaluated by irradiating operating diodes with transient ionizing radiation. Leakage current was induced in diffused junction GaAs and silicon X-band IMPATT diodes by irradiation with 100 nsec pulses of 10 MeV electrons. With increasing leakage current, the oscillator RF power decreases and the frequency of oscillation increases. A large signal circuit model of the IMPATT diode is developed which correlates well with experimental measurements.     

High-power P-i-N diode with local lifetime control using palladium diffusion controlled by radiation defects

We demonstrate for the first time a high-power P-i-N diode with local lifetime control using palladium (Pd) diffusion. Low-temperature (600/spl deg/C-700/spl deg/C) diffusion of Pd is stimulated by radiation defects resulting from alpha-particle irradiation (/sup 4/He/sup 2+/: 10 MeV, 10/sup 12/ cm/sup -2/). The region of maximal radiation damage of Gaussian shape is decorated by substitutional Pd after diffusion from a palladium silicide surface layer through the P/sup +/--P region into the N-base close to the anode junction. Significantly lower leakage current compared to that of standard /sup 4/He/sup 2+/ irradiation and very good ruggedness under fast recovery (di/dt/spl ap/500 A//spl mu/s, V/sub R//spl ap/2 kV) is demonstrated for Pd diffusion at 600/spl deg/C.     

高压功率快恢复二极管的寿命控制研究

利用质子辐照感生的空位缺陷对铂原子的汲取作用,获得了局域寿命控制,辅以能量为4MeV电子辐照整体寿命控制技术,在具有低阳极发射效率结构的高压功率快恢复二极管中实现了更好的综合性能的优化。测试结果表明,此类快恢复二极管具有反向恢复时间短、软度大、反向漏电低的优良特性,在国际上处于领先水平。     

The role of electronic energy loss in SHI irradiated Ni/oxide/n-GaP Schottky diode

The impact of energy loss mechanism by 100 MeV Au^8 + ion on the dielectric parameters of Ni/oxide/n-GaP Schottky diode was studied under different fluences. The Schottky barrier height, donor ion concentration and interface states density of the diode were varied considerably under different ion fluence. The various dielectric parameters were altered significantly by the ion fluence. The reduction in dielectric constant after irradiation was ascribed to screening of space charge polarization due to reduction in interface states density. The relaxation peak of imaginary electric modulus indicates hopping type conduction mechanisms in the intermediate voltage range. The sensitive behavior of dielectric parameters with fluence dose was attributed to the alteration of interface state density due to high electronic energy loss of 100 MeV Au^8 + ions at the interface.     

一种积累型槽栅超势垒二极管

提出了一种积累型槽栅超势垒二极管,该二极管采用N型积累型MOSFET,通过MOSFET的体效应作用降低二极管势垒。当外加很小的正向电压时,在N+区下方以及栅氧化层和N-区界面处形成电子积累的薄层,形成电子电流,进一步降低二极管正向压降;随着外加电压增大,P+区、N-外延区和N+衬底构成的PIN二极管开启,提供大电流。反向阻断时,MOSFET截止,PN结快速耗尽,利用反偏PN结来承担反向耐压。N型积累型MOSFET沟道长度由N+区和N外延区间的N-区长度决定。仿真结果表明,在相同外延层厚度和浓度下,该结构器件的开启电压约为0.23 V,远低于普通PIN二极管的开启电压,较肖特基二极管的开启电压降低约30%,泄漏电流比肖特基二极管小近50倍。     

The effects of the temperature and annealing on current-voltage characteristics of Ni/n-type 6H-SiC Schottky diode

The temperature dependence of current-voltage (I-V) characteristics of as-fabricated and annealed Ni/n-type 6H-SiC Schottky diode has been investigated in the temperature range of 100-500 K. The forward I-V characteristics have been analysed on the basis of standard thermionic emission theory. It has been shown that the ideality factor (n) decreases while the barrier height (Φ_b) increases with increasing temperature. The values of Φ_b and n are obtained between 0.65-1.25 eV and 1.70-1.16 for as-fabricated and 0.74-1.70 eV and 1.84-1.19 for annealed diode in the temperature range of 100-500 K, respectively. The I-V characteristics of the diode showed an increase in the Schottky barrier height, along with a reduction of the device leakage current by annealing the diode at 973 K for 2 min.