Schottky barriers on InSb

Schottky barriers formed on air-cleaved InSb are found to be more reproducible and have less leakage than diodes fabricated by chemical processing. Etched surfaces yield diodes with large leakage currents and high series resistances whose values are correlated, i. e. , high series re-sistances have less leakage and vice versa. With air-cleaved surfaces the lowest leakage is observed when the surfaces adjoining the contact are covered with SiO₂. From C^-2 versus V data, barrier heights of 50 mV and 175 mV at 77K are measured for Au contacts to n- and p-type InSb, respectively. The current-voltage characteristics of Au contacts are consistent with these barriers, but the low-temperature field-emission behavior appears to be dom-inated by tunneling via traps. For Pb contacts, deep-level traps are in evidence that can lead to erroneous in-terpretations of C^-2 versus V voltage intercepts. The I-V data for Pb contacts suggest V_Bn ≈0 and V_Bp ≈E_g/q. Diodes fabricated on vacuum-cleaved surfaces have large leakage currents which result from the etching procedures introduced to isolate individual diodes.     

Schottky barriers fabricated on glow discharge A-Si:H films deposited under bias

Hydrogenated amorphous silicon films were deposited in a three electrode dc glow discharge system under the substrate bias. The composition of the films, using infrared spectroscopy, has been investigated. The photovoltaic parameters of the fabricated Au and Pt Schottky barrier structures have been measured. The purpose of this study was to determine if polarization of the substrates influence the properties of the deposited a-Si:H films. At present with the EECS Department, University of Santa Clara, Santa Clara, California 95053. At present with the Eaton Corporation, Milwaukee, Wisconsin 53216.     

Aluminium Schottky barriers on sputter-etched silicon

Schottky barriers have been prepared by sputter-etching a silicon surface immediately prior to the deposition, by sputtering, of an aluminium electrode. The barrier height measured on these diodes is nearly identical to the height found previously for barriers made by cleaving silicon in a vacuum in a stream of evaporating aluminium species. This suggests that the barrier height is controlled by surface states.     

Schottky barriers on n-GaN grown on SiC

Characteristics of Schottky barriers fabricated on n-type GaN were investigated. The barriers were formed by vacuum thermal evaporation of Cr, Au, and Ni. Current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the barriers were measured in a wide temperature and current density range. Fundamental parameters (barrier height and built-in potential) of the Schottky barriers were determined. The dependence of the barrier ideality factor on doping concentration in GaN was measured. Correlation between the barrier height and metal work function was observed. The electron affinity for GaN was determined using both C-V and I-V characteristics. The current flow mechanism through the barriers is discussed.     

Schottky rectifiers on silicon using high barriers

Schottky diodes are presently used for power rectification because of their low forward voltage drop. However, they have only been fabricated on relatively low resistivity and thin semiconductor layers. Hence the reverse breakdown voltages are low. To make diodes that stand higher reverse voltages, low doped material of sufficient thickness is necessary. Ordinary Schottky barriers do not inject minority carriers and the resistive voltage drop at high forward currents will be large, However, for high Schottky barriers ～ 0.9eV, minority carriers are injected and the series resistance is decreased.In this paper we report results from one-dimensional numerical calculations as well as experimental results of high barrier Schottky diodes. We discuss the voltage drop at high forward currents for different substrate resistivity and thickness, as well as values of the high barrier.     

Hafnium-ntype silicon Schottky barriers

This paper describes the electrical properties of hafnium-/n-type/silicon contacts. These contacts were found to be Schottky barriers with a low barrier height. Polished and chemically cleaned 〈111〉 silicon wafers with a donor concentration N_d = 7 × 10²² m^?3 were used to fabricate experimental Schottky barrier structures. For the Schottky barrier height φ_bn and the ideality factor n values were found of 0.47 V and 1.07–1.11, respectively. It is concluded that due to their low forward voltage drop and good rectifying properties, Hf-nSi contacts can be applied in microwave Schottky barrier diodes.     

铂—硅合金形成硅化铂的研究

本文对 PtSi 红外肖特基势垒探测器中硅化铂薄层(～20nm)进行了分析,比较了不同制作条件 PtSi 薄层的化学组成以及有关元素在薄层中的纵向分布等情况,提出了良好的硅化铂薄层的形成条件,并测出了以此条件制作的 PtSi 红外肖特基势垒探测器参数 D~*=2.8×10~(10)cm·H_z~(1/2)W~(-1),势垒高度φ_(ms)=0.21eV。     

Effect of annealing temperature on the electrical characteristics of Platinum/4H-SiC Schottky barrier diodes

Pt/4H-SiC Schottky barrier diodes have been fabricated to investigate the effect of annealing on the electrical characteristics of the fabricated devices. The parameters such as barrier height, ideality factor and donor concentration were deduced from the current–voltage (I–V) and the capacitance–voltage (C–V) measurements at room temperature. Diodes showed non-ideal behaviour like high value of ideality factor and lower value of barrier height. A barrier height of 1.82?eV was obtained from C–V measurements and it was 1.07?eV when obtained from the I–V measurements with ideality factor 1.71 for as-deposited diodes at room temperature. The diodes, therefore, were annealed in the temperature range from 25°C to 400°C to observe the effect of annealing temperature on these parameters. Schottky barrier height and ideality factors were found to be temperature-dependent. After rapid thermal annealing upto 400°C, a barrier height of 1.59?eV from C–V measurements and the value of 1.40?eV from I–V measurements with ideality factor 1.12 were obtained. Barrier heights deduced from C–V measurements were consistently larger than those obtained from I–V measurements. To come to terms with this discrepancy, we re-examined our results by including the effect of ideality factor in the expression of the barrier height. This inclusion of ideality factor results in reasonably good agreement between the values of barrier height deduced by the above two methods. We believe that these improvements in the electrical parameters result from the improvement in the quality of interfacial layer.     

退火对Pt/TiO2肖特基二极管结构及电学性能的影响

以硅为衬底,采用射频磁控溅射技术制备了TiO2薄膜,利用扫描电子显微镜及拉曼光谱对退火前后的TiO2进行表征与结构分析.结果表明,退火后的TiO2具有良好的结晶特性,且呈锐钛矿结构.在此薄膜工艺条件下,以TiO2为半导体层在玻璃基底上制备了Al/TiO2/Pt肖特基二极管,并在153～433 K温度范围内对其进行了I-V测试,得到以下结果:在整个温度范围内,A1/TiO2/Pt肖特基二极管均表现出良好的整流特性;其理想因子随温度升高而降低,势垒高度随温度升高而升高;在433 K下,理想因子为1.31,势垒高度为0.73,表明此肖特基二极管已接近理想的肖特基二极管.     

大束流离子注入形成P-Si CoSi2/Si肖特基结的电学特性

采用金属离子注入法形式 Co Si2 /Si肖特基结并分析电学特性。分别测量不同退火条件下样品的 I-V、C-V特性 ,得出了各样品的势垒高度、串联电阻和理想因子。结果表明 ,采用快速热退火方法形成的结性能较好     

ICP刻蚀损伤对n-GaN-Ni/Au肖特基接触特性的影响

通过电流-电压法(I-V),电容-电压法(C-V)对n-GaN材料的ICP(感应耦合等离子体)刻蚀样品和未刻蚀样品上的肖特基势垒二极管的电学特性进行了分析.利用原子力显微镜(AFM)和扫描电镜(SEM)对刻蚀样品的表面形貌,以及退火前后肖特基接触金属的表面形貌变化进行了研究.试验表明,ICP刻蚀会在GaN表面引入损伤,形成电子陷阱能级从而引起肖特基二极管的势垒高度降低,理想因子增大,反向泄漏电流增大.刻蚀样品在400 ℃热退火可以恢复二极管的电特性,退火温度到600 ℃时二极管特性要好于未刻蚀的样品.     

快热退火对Co/n-Poly-SiGe肖特基结I-V-T特性的影响

采用射频磁控溅射法在n-Si(100)衬底上沉积Si1-xGex薄膜,俄歇电子谱(AES)测定Si1-xGex薄膜的Ge含量约为17%。对薄膜进行高温磷扩散掺杂,制得n-poly-Si0.83Ge0.17。在n-poly-Si0.83Ge0.17薄膜上溅射一层Co膜,制成Co/n-poly-Si0.83Ge0.17/n-Si肖特基结样品。在300～600℃范围内,对样品做快热退火。对不同退火温度下的样品做I-V-T测试。研究发现,测试温度升高,不同退火温度样品的肖特基势垒高度(SBH)的差别变小,500℃退火的样品,表观SBH最小。总体上,SBH随测试温度的升高而变大,理想因子的变化趋势则与之相反。基于SBH的不均匀分布建模,对实验结果给出了较为合理的解释。     

Solar cells using discharge-produced amorphous silicon

Thin film solar cells, ≲ 1 μm thick, have been fabricated in p-i-n and Schottky barrier structures using d.c. and r.f. glow discharges in silane. Conversion efficiencies in the range of 2.5 to 4.0% have been obtained with both structures. The p-i-n cells exhibit built-in potentials of ∼ 1.1 V while the Pt Schottky barrier cells have barrier heights of ∼ 1.1 eV. The dark currents in the p-i-n cells appear to be recombination-limited while the Schottky barrier cells exhibit near-ideal diode characteristics with diode quality factors near unity.     

Hydrogen sensitivity of palladium?thin-oxide?silicon Schottky barriers

It is shown that current transport through Schottky barriers formed by Pd on n-type silicon with a thin thermally grown oxide is sensitive to hydrogen in the ambient. It is shown that a transition from minority- to majority-carrier dominated current occurs with increasing hydrogen pressure.     

n-GaN肖特基势垒紫外光探测器的电子辐照效应

研究了n型Au/GaN肖特基势垒紫外光探测器的电子辐照失效机理.从实验中观测到,随着电子辐照注量的不断增加,Au/GaN间辐照诱生的界面态引起器件的击穿电压明显减小,反向漏电流逐渐增大.辐照诱生的深能级缺陷导致紫外光探测器对较长波长光的吸收,使得UV探测器中可见光成分的背景噪声增加.同时,对辐照后的GaN肖特基紫外光探测器进行了100℃以下的退火处理,退火后,器件的电流-电压特性有所改善.     

反应溅射法制备耐熔金属氮化物/GaAs肖特基结

自对准GaAs场效应晶体管工艺要求非常稳定的材料作为栅电极,经高温退火过程后它仍必须与衬底保持良好的肖特基接触。本文总结了近几年来有关耐熔金属氮化物/GaAs肖特基结的研究工作,对取得的进展及存在的问题进行了讨论。     

基于肖特基二极管传输型预失真器设计

本文提出了一种基于肖特基二极管传输型预失真器,由两个肖特基二极管并联来构成的,可以通过调整二极管偏置电压来对其幅度和相位特性进行调节。本文先对该传输型预失真器的原理进行了分析,给出了其等效电路,并对该等效电路进行了分析;然后通过ADS 对该二极管传输型预失真器进行了仿真。仿真结果表明该预失真器能够有效的改善功率放大器的线性度。     

退火温度对Au/Ti/4H-SiC肖特基接触特性的影响

采用电子束蒸发法在4H-SiC表面制备了Ti/Au肖特基电极,研究了退火温度对Au/Ti/4H-SiC肖特基接触电学特性的影响.对比分析了不同退火温度下样品的电流密度-电压(J-V)和电容-电压(C-V)特性曲线,实验结果表明退火温度为500℃时Au/Ti/4H-SiC肖特基势垒高度最大,在.J-V测试和C-V测试中分别达到0.933 eV和1.447 eV,且获得理想因子最小值为1.053,反向泄漏电流密度也实现了最小值1.97×10-8 A/cm2,击穿电压达到最大值660 V.对退火温度为500℃的Au/Ti/4H-SiC样品进行J-V变温测试.测试结果表明,随着测试温度的升高,肖特基势垒高度不断升高而理想因子不断减小,说明肖特基接触界面仍然存在缺陷或者横向不均匀性,高温下的测试进一步证明肖特基接触界面还有很大的改善空间.     

On the transport theory of Schottky barriers to polycrystalline silicon thin films

A theoretical investigation of electronic transport in metal contacts to polycrystalline silicon thin films is presented. Calculations based upon the reported values of grain-boundary potentials indicate that the thermionic emission theory may be applied to the majority-carrier transport only for low bias voltages. At larger bias voltages, one needs to take account of the voltage lost to the space-charge regions adjacent to the grain boundaries, and a transition from electrode-limited to bulk-limited majority-carrier transport results. We further demonstrate that the injection of minority carriers can dominate the dark current for a range of grain size and interface state densities at the grain boundaries. Under these conditions, the current obeys anexp (qV/2kT)dependence reminiscent of space-charge recombination, although the origin of the current in this case is minority-carrier diffusion current, with recombination only at grain boundaries in the neutral region. This is a special case of the "high-injection" regime observed in single crystals, but in the present situation it is found even for low bias voltages as a consequence of the band bending at the grain boundaries, which makes the material nearly intrinsic at these points. Finally, we show that the effective minority-carrier diffusion length for the injected carriers under dark conditions itself increases with bias voltageVapproximately asexp (qV/2kT), in striking contrast to previous treatments.