The reverse anneal of junction characteristics in forming shallow p+-n junction by BF2+ implantation intothin Co films on Si substrate

Silicided shallow p⁺-n junctions, formed by BF₂ ⁺ implantation into thin Co films on Si substrates and subsequently annealed, showed a reverse anneal of junction characteristics in the temperature range between 550 and 600°C. The reverse anneal means behavior showing degradation of the considered parameters with increasing annealing temperature. A higher implant dosage caused a more distinct reverse anneal. The reverse anneal of electrical characteristics was associated with the reverse anneal of substitutional boron. A shallow p⁺-n junction with a leakage current density lower than 3 nA/cm₂, a forward ideality factor of better than 1.01, and a junction depth of about 0.1 μm was achieved by just a 550°C anneal     

The influence of Ge-implantation on the electrical characteristicsof the ultra-shallow junction formed by using silicide as a diffusionsource

The electrical characteristics of ultra-shallow p⁺/n junctions formed by implanting a 60 keV Ge⁺ into a TiSi₂ layer have been studied. A very low reverse leakage current density (≅0.4 nA/cm² at -5 V) and a very good forward ideality factor n (≅1.001) were achieved in these ultra-shallow p ⁺/n junctions. From the secondary ion mass spectrometry (SIMS) analysis, the junction depth was measured to be 600 Å and the surface concentration was about 3 times higher than that of the conventional samples     

The current-voltage-temperature characteristics of Al/NPB/p-Si contact

The current-voltage (I-V) characteristics of the Al/NPB/p-Si contact shows rectifying behavior with a potential barrier formed at the contact interface. The barrier height and ideality factor values of 0.65 eV and 1.33 are measured at the forward bias of the diode. The barrier height of the Al/NPB/p-Si diode at room temperature is larger that (∼0.58 eV) of conventional Al/p-Si diode. It reveals the NPB organic film control the carrier transport of the diode at the contact interface. The temperature effect on the I-V measurement is also performed to reveal the junction characteristics. The ideality factor of the Al/NPB/p-Si contact increases with decreasing temperature. And the barrier height decreases with decreasing temperature. The effects are due to the existence of the interface states and the inhomogeneous of the barrier at the junction.     

Investigation of Al Schottky junction on n-type CdS film deposited on polymer substrate

A systematic study has been made on the behavior of Al/n-CdS thin film junction on flexible polymer substrate (polyethylene terephthalate, PET) grown using thermal evaporation method. Temperature dependence of I-V measurements for this junction has been done which closely follow the equations of Schottky barrier junction dominated by thermionic emission mechanism. Intrinsic and contact properties such as barrier height, ideality factor and series resistance have been calculated from I-V characteristics. The barrier height of Al/n-CdS junction is found to increase with increase in temperature whereas ideality factor and series resistance decrease with increase in temperature.     

Current transport and formation of energy structures in narrow Au/n-GaAs Schottky diodes

The current transport and formations of potential barrier height in narrow Au/n-GaAs Schottky diodes (SD) with a contact surface in length of 200 μm, width of 1 and 4 μm have been investigated.It was determined that features of current transport are in good agreements with the thermionic emission theory in the forward bias as like high-quality conventional (flat) SD. Features of current transport in the reverse bias also is well described by thermionic emission theory, but it has specific features unlike I–V characteristics flat SD.Forward bias of narrow SD current–voltage (I–U) characteristics are represented by straight lines in semi-logarithmic scale in a wide range, nearly nine order of current up to 0.7 V with near unit ideality factor. In the beginning of the reverse voltage, the current practically was extremely low, by increasing in voltage the current jump in steps approximately for 3–4 order in voltage of 3–4 V, then current increases linear for 3–5 order in semi-logarithmic scale by increasing in voltage up to nearly 7 V.Numerical values of parameters such as the saturation currents, the operating barrier height, ideality factor, dimensionless factor are obtained. The correlations between ideality factor and dimensionless factor were meaningful.The energy diagrams of narrow SD have been drawn in absence and presence of forward and reverse voltage. It is found that electronic processes in narrow SD are well described by energy model of real narrow metal–semiconductor contacts. The additional electric field arising in near contact area of the semiconductor because of creating contact potential difference between contact surface and to it adjoining free surfaces of the metal and semiconductor.     

InGaAsSb/InP Double Heterojunction Bipolar Transistors Grown by Solid-Source Molecular Beam Epitaxy

This letter investigates the dc characteristics of a double heterojunction bipolar transistor (DHBT) with a compressively strained InGaAsSb base, which is grown by solid-source molecular beam epitaxy. The novel InP/InGaAsSb HBT has a lower base/emitter (B/E) junction turn-on voltage, a lower offset voltage, and a junction ideality factor closer to unity than the conventional InP/InGaAs composite collector DHBT. These characteristics are attributed to the transistor's type-I B/E junction and type-II base/collector junction, which facilitates carrier transport for low power, high current density, and high-speed operation. Heterojunction bipolar transistors (HBTs), InP/InGaAsSb, molecular beam epitaxy (MBE).     

多孔硅的电致发光

采用横向阳极氧化技术在n型单晶硅衬底上制备多孔硅,室温下光荧光谱峰值位于688nm;表面蒸铝形成铝/多孔硅/硅的类肖特基结构,并观察到采用这种方法生长的多孔硅样品的室温电致发光。铝/多孔硅结具有良好的整流特性,在-10V内反向漏电流小于50nA,理想因子为7。室温电致发光的阈值电流为8.5mA,发光强度随正向电流的增加而加强。     

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     

2 μm InGaSb/AlGaAsSb量子阱激光器理想因子的研究

展示了一种低阈值（~131 A/cm2）2m InGaSb/AlGaAsSb单量子阱（Single Quantum Well,SQW）激光器,并对该激光器的理想因子n进行了研究。激光器的总体理想因子n由中央pn结的理想因子n和n型GaSb衬底与n型金属之间形成的整流结的理想因子n两部分组成。当温度从20℃升高到80℃时,激光器的总体理想因子n从4.0降低至3.3。该结果与所使用的理论模型以及独立的GaSb材料整流结（pn结、GaSb/金属结等）理想因子n的数值是相吻合的。     

Numerical analysis of inhomogeneous Schottky diode with discrete barrier height patches

The potential profile inside the semiconductor at the metal–semiconductor contact is simulated by numerically solving the Poisson equation and the drift diffusion equations for inhomogeneous Schottky diode. From the simulated potential and the electron and hole concentrations, the drift-diffusion current as a function of bias is calculated. The simulation is carried out for various distribution patterns of barrier height patches at the metal–semiconductor contact to study the effect of barrier inhomogeneities on the Schottky diode parameters, namely barrier height and ideality factor and their temperature dependence. It is found that barrier height decreases and ideality factor increases with increase in the deviation of discrete barrier height patches in the distribution. The resulting barrier parameters are studied to understand the effect of barrier inhomogeneities on the current–voltage characteristics of inhomogeneous Schottky contact.     

Electrical characterization of inorganic-on-organic diode based InP and poly(3,4-ethylenedioxithiophene)/poly(styrenesulfonate) (PEDOT:PSS)

The electronic properties of metal–organic semiconductor-inorganic semiconductor diode between InP and poly(3,4-ethylenedioxithiophene)/poly(styrenesulfonate) (PEDOT:PSS) polymeric organic semiconductor film have been investigated via current–voltage and capacitance–voltage methods. The Al/PEDOT:PSS/p-InP contact exhibits a rectification behavior with the barrier height value of 0.98 eV and with the ideality factor value of 2.6 obtained from their forward bias current voltage (I–V) characteristics at the room temperature greater than the conventional Al/p-InP (0.83 eV, n = 1.13). This increase in barrier height and ideality factor can be attributed to PEDOT:PSS film formed at Al/p-InP interface.     

Low-temperature growth of silicon-boron layer as solid diffusionsource for polysilicon contacted p+-n shallow junction

A new material, Si-B, is proposed as a solid diffusion source for fabrication of poly-Si contacted p⁺-n shallow junctions. The junction depth of the Si-B source diode has been measured and compared with that of a BF₂⁺-implanted poly-Si source diode. It was found that the Si-B source diode had a much shallower junction and was less sensitive to thermal budget than the BF₂⁺ source diode. This was attributed to the smaller surface concentration and diffusivity of boron in the silicon in Si-B source diodes. Regarding electrical characteristics of diodes with a junction depth over 500 Å, a forward ideality factor of better than 1.01 over 8 decades and a reverse-current density lower than 0.5 nA/cm² at -5 V were obtained. As the junction depth shrank to 300 Å, the ideality factor and reverse current density of diodes increased slightly to 1.05 and 1.16 nA/cm², respectively. These results demonstrated that a uniform ultrashallow p⁺-n junction can be obtained by using a thin Si-B layer as a diffusion source     

Fully ion-implanted abrupt pn junction on semi-insulating InP

We report a fully ion-implanted pn junction using Si for n-implant and P/Be co-implant for a shallow p+ surface layer. C/V measurements indicate abrupt junction behaviour. Mesa diodes were fabricated and showed an ideality factor of two, small leakage current and avalanche breakdown at reverse bias greater than 40 V.     

激光二极管正向电特性的精确检测

采用正向交流特性结合I-V特性的方法,检测了激光二极管的串联电阻、理想因子、结电压和结电容与外加电压或电流的关系.首次发现,激光二极管的结电压、串联电阻、理想因子和结电容在阈值附近同时出现了明显的阶跃,之后结电压呈现饱和.此外还观察到,在较低的测试频率和较大的正向电压下,激光二极管的结电容具有负值.     

Elevated n+/p junctions by implant into CoSi2formed on selective epitaxy for deep submicron MOSFETs

Very shallow elevated n⁺/p junctions formed by arsenic implant into or through cobalt silicide (CoSi₂) formed on selective epitaxial layers and their application to deep submicron n-channel MOSFETs were studied for the first time. PREDICT 1.6 simulation program was employed to choose the desired implant energies and annealing thermal cycle based on theoretically predicted silicide thickness. The implanted CoSi₂ elevated junctions had low reverse current and no bias voltage dependence up to 5 V. Diffusion current dominated the junction forward current, and good ideality factors close to 1 were obtained. A nearly abrupt junction doping profile was achieved. Deep submicron n-channel MOSFETs incorporating implanted CoSi₂ elevated junctions were demonstrated. Sharp turn-off and reasonably large drain currents were achieved     

Barrier height and ideality factor dependency on identically produced small Au/p-Si Schottky barrier diodes

Small high-quality Au/P-Si Schottky barrier diodes (SBDs) with an extremely low reverse leakage current using wet lithography were produced. Their effective barrier heights (BHs) and ideality factors from current-voltage (Ⅰ-Ⅴ) characteristics were measured by a conducting probe atomic force microscope (C-AFM). In spite of the identical preparation of the diodes there was a diode-to-diode variation in ideality factor and barrier height parameters. By ex-trapolating the plots the built in potential of the Au/p-Si contact was obtained as Vbi = 0.5425 V and the barrier height value φB(C-V) was calculated to be φB(C-V) = 0.7145 V for Au/p-Si. It is found that for the diodes with diameters smaller than 100 μm, the diode barrier height and ideality factor dependency to their diameters and correlation between the diode barrier height and its ideality factor are nonlinear, where similar to the earlier reported different metal semi-conductor diodes in the literature, these parameters for the here manufactured diodes with diameters more than 100μm are also linear. Based on the very obvious sub-nanometer C-AFM produced pictures the scientific evidence behind this controversy is also explained.     

Procedure for determining diode parameters at very low forward voltage

A technique is proposed to extract the reverse saturation current parameter and ideality factor of semiconductor junctions from the low forward voltage region of the device’s characteristics. The method involves performing a mathematical operation on the experimental data that allows to calculate the parameters at values of forward current smaller than the reverse saturation current. The procedure was tested and its accuracy verified on synthetic I–V characteristics, with and without added simulated experimental error or noise. Good agreement is obtained between the parameters used in modeling and the extracted values. The procedure was also applied to experimentally measured I_B–V_BE characteristics of a real power BJT.     

Characteristics of sub-100-nm p+/n junctions fabricatedby plasma immersion ion implantation

Plasma immersion ion implantation (PIII) is an efficient method for fabricating high-quality p⁺/n diodes with junction depths below 100 nm. SiF₄ is implanted to create an amorphous Si layer to retard B channeling and diffusion, and then BF₃ is implanted. Ultrashallow p⁺/n junctions are formed by annealing at 1060 °C for 10 s. With the shallow implants, no extended defects are observed in device or peripheral areas due to rapid outdiffusion of fluorine. Diode electrical characteristics yield forward ideality factor of 1.05-1.06 and leakage current density below 2 nA/cm ² in the diode bulk. Minority-carrier lifetime below the junction is greater than 250 μs     

肖特基接触的机理及不均匀性研究

对一般情况下肖特基接触的机理和肖特基势垒高度的影响因素做了系统分析,研究了肖特基接触特性的不均匀性及其原因,指出多晶界面势垒高度比同种材料的要低。通过实验,研究了金属/n-poly-Si0.83Ge0.17肖特基结的I-V-T特性,得到了势垒高度及影响因子与测试温度和外加偏压的依赖关系。研究发现:随着测试温度升高,表观理想因子变小,肖特基势垒高度变大;外加偏压增大,表观势垒高度和理想因子均变大。基于肖特基接触的不均匀性进行建模,得到了退火样品的表观势垒高度和理想因子近似为线性负相关的结论。     

High-performance polysilicon contacted shallow junctions formed bystacked-amorphous-silicon films

A high-performance polysilicon contacted shallow junction diode formed by using a stacked-amorphous-silicon (SAS) film as the diffusion source is reported. The diode exhibited a very low leakage current (⩽1 nA/cm² at -5 V), a very high breakdown voltage (⩾100 V), and a forward ideality factor m⩽1.05 over seven decades