有源层溅射温度对非晶铟镓锌氧薄膜晶体管电学特性的影响

The effect of active layer deposition temperature on the electrical performance of amorphous InGaZnO （a-IGZO） thin film transistors （TFTs） is investigated. With increasing annealing temperature, TFT performance is firstly improved and then degraded generally. Here TFTs with best performance defined as ＂optimized-annealed＂ are selected to study the effect of active layer deposition temperature. The field effect mobility reaches maximum at deposition temperature of 150℃ while the room-temperature fabricated device shows the best subthreshold swing and off-current. From Hall measurement results, the carrier concentration is much higher for intentional heated a-IGZO films, which may account for the high off-current in the corresponding TFT devices. XPS characterization results also reveal that deposition temperature affects the atomic ratio and Ols spectra apparently. Importantly, the variation of field effect mobility of a-IGZO TFTs with deposition temperature does not coincide with the tendencies in Hall mobility of a-IGZO thin films, Based on the further analysis of the experimental results on a-IGZO thin films and the corresponding TFT devices, the trap states at front channel interface rather than IGZO bulk layer properties may be mainly responsible for the variations of field effect mobility and subthreshold swing with IGZO deposition temperature.     

衬底温度和氮气分压对氮化锌薄膜的性能影响

采用射频磁控溅射法在不同衬底温度和不同氮气分压下在石英玻璃衬底上制备氮化锌薄膜. 利用XRD和喇曼散射仪分析了样品的晶体结构和组成. 结果表明当氮气分压为1/2时可以生成多晶单一相的氮化锌薄膜. 利用霍尔效应和光学透过谱测量了样品的电学和光学性质. 结果表明衬底温度对样品的电学和光学性质有很大的影响. 衬底温度从100℃上升到300℃时,样品的电阻率从0.49降低到0.023Ω·cm. 电子浓度从2.7×1016升高到8.2×1019cm-3. 在衬底温度为200℃,氮气分压为1/2时,样品的光学带隙为1.23eV.     

二次大气退火对于非晶铟镓锌氧化物薄膜晶体管电学特性的影响

介绍了非晶铟镓锌氧化物薄膜晶体管(a-IGZO TFT)的制备,并在不同环境下进行了退火.其中,经过一次退火冷却后再进行第二次退火的器件表现出了最佳的电学性能,相比其他器件有较小的亚阈值摆幅(～1.43V/decade)和更好的磁滞稳定性.通过对比其他退火条件下的器件表现与工艺,发现在一次退火基础上增加的较短时间(30min)退火是这些显著提高的主要原因.这说明,在a-IGZO TFT进行了一次退火并冷却后,通过引入二次退火使得a-IGZO薄膜表面平整化和结构密实化,器件性能仍然有提高的空间.     

环境湿度对非晶铟镓锌氧薄膜晶体管负偏压光照稳定性的影响

为了探究环境湿度对非晶铟镓锌氧薄膜晶体管(a-IGZO TFT)的负偏压光照(NBIS)稳定性的影响,本文使用非密闭腔室进行不同波长光照射下以及不同相对湿度下的TFT负偏压测试.介绍了a-IGZO TFT的基本结构以及实验所用I-V测试系统.测试了不同波长光照条件下a-IGZO TFT的转移特性曲线以及相同波长光照射下...     

八羟基喹啉锌非晶薄膜器件的制备和开关特性

介绍了八羟基喹啉锌（Znq2）有机薄膜及器件的制备方法. X射线衍射谱指出，用真空蒸发方法制备的Znq2薄膜呈非晶态结构；通过对Znq2有机薄膜I-V曲线的分析，揭示了Znq2薄膜的开关特性. 基于分子在电场作用下的空间取向的变化，对这一现象提出了一种可能的理论解释.     

八羟基喹啉锌非晶薄膜器件的制备和开关特性

介绍了八羟基喹啉锌(Znq2)有机薄膜及器件的制备方法.X射线衍射谱指出,用真空蒸发方法制备的Znq2薄膜呈非晶态结构;通过对Znq2有机薄膜I-Ⅴ曲线的分析,揭示了Znq2薄膜的开关特性.基于分子在电场作用下的空间取向的变化,对这一现象提出了一种可能的理论解释.     

溅射功率对氮化锌薄膜特性的影响

在玻璃衬底上通过磁控反应溅射法,利用纯金属Zn靶,在N2-Ar等离子体氛围中制备出氮化锌薄膜。X射线衍射谱表明氮化锌具有(4 0 0)择优取向,反方铁锰矿结构。研究了溅射功率对氮化锌薄膜结构、电学及光学性质的影响。     

射频溅射功率对非晶Zn-Sn-O薄膜性能的影响

使用射频磁控溅射法,基于不同溅射功率(58、79、116、148和171W)条件在玻璃基底上室温制备了Zn-Sn-O(ZTO)薄膜,并探讨了溅射功率对薄膜的结构、电学性能和光学性能的影响。结果表明,提高溅射功率有助于提升薄膜的沉积速率;XRD分析表明不同溅射功率条件下制备的ZTO薄膜均具备稳定的非晶结构;随着溅射功率的增加,薄膜的电阻率下降,光学吸收边“红移”(光学禁带宽度从3.77eV减小到3.62eV);整体来看,在58~148W溅射功率范围内制备的ZTO薄膜具备较好的可见光透明性,其在380~780nm可见光范围内的平均透过率均超过85%。     

直流和交流溅射沟道材料对铟镓锌氧薄膜晶体管性能的影响

研究了在TFT制备过程中,直流溅射和交流溅射生长铟镓锌氧薄膜对器件的转移特性和栅偏压应力特性的影响。交流溅射生长的IGZO制备的器件具有较低的阈值电压和较好的亚阈特性,分别为0.937 V和0.34 V/dec;而直流溅射得到的阈值电压和亚阈值摆幅则分别是:1.78V和0.50 V/dec。对于稳定性,在30 V的栅极应力下,直流溅射得到的器件的阈值电压漂移则相对小一些。本文通过分析直流和交流溅射的过程中薄膜的沉积情况,阐述了上述现象产生的原因。     

离子注入对ITO薄膜电学特性的影响

对系列In2O3∶Sn (ITO)薄膜样品分别实施了不同剂量的Sn+, Ag+ 和Mo+离子注入并将它们在250 ℃下进行了热处理.利用霍耳测量研究了原始样品及注入和退火前后各样品的电学特性.研究了ITO薄膜的电学参数受离子注入的种类及剂量的影响.实验证明不同种类的离子注入会不同程度地降低ITO的导电性能,但热处理的效应与之相反.3种金属中,Sn+离子对薄膜造成的注入损伤最小,而高价的钼离子可以替换铟离子的位置成为施主,当注入剂量为1×1015 cm-2时,经过Mo+离子注入和后续退火的ITO薄膜,载流子浓度提高了14%.     

Magnetic properties of ZnO:Cu thin films prepared by RF magnetron sputtering

ZnO films and ZnO:Cu diluted magnetic semiconductor films were prepared by radio frequency magnetron sputtering on Si (111) substrates, with targets of ZnO and Zn0.99Cu0.01 O, respectively. The plasma emission spectra were analyzed by using a grating monochromator during sputtering. The X-ray photoelectron spectroscopy measurements indicate the existence of Zni defect in the films, and the valence state of Cu is 1. The X-ray diffraction measurements indicate that the thin films have a hexagonal wurtzite structure and have a preferred orientation along the c-axis. The vibrating sample magnetometer measurements indicate that the sample is ferromagnetic at room temperature, and the origin of the magnetic behavior of the samples is discussed.     

射频磁控溅射法制备ZnO:Cu薄膜的磁性研究

ZnO films and ZnO：Cu diluted magnetic semiconductor films were prepared by radio frequency mag-netron sputtering on Si （111） substrates, with targets of ZnO and Zn0.99Cu0.01O, respectively. The plasma emission spectra were analyzed by using a grating monochromator during sputtering. The X-ray photoelectron spectroscopy measurements indicate the existence of Zni defect in the films, and the valence state of Cu is 1＋. The X-ray diffraction measurements indicate that the thin films have a hexagonal wurtzite structure and have a preferred orientation along the c-axis. The vibrating sample magnetometer measurements indicate that the sample is ferromagnetic at room temperature, and the origin of the magnetic behavior of the samples is discussed.     

Effects of annealing temperature on the photoluminescence of RF sputtered Barium titanate thin films

BaTiO₃ thin films were deposited onto quartz substrates by an RF magnetron sputtering method. The films deposited at room temperature and annealed at 773–1173 K were characterized using X-ray diffraction (XRD)Scanning electron microscopy (SEM), UV–vis spectroscopy and Photoluminescence spectroscopy (PL). X-ray diffraction studies revealed that the film is amorphous in nature at 773 K and that the crystallinity increases with increase in annealing temperature. The average crystallite size of the films increased from 13–18 nm and the optical band gap decreased in the range of 4.33–3.43 eV, with increase in annealing temperature. The films exhibited good adherence to the substrates and the SEM images showed smooth surface morphology. Energy dispersive X-ray (EDX) analysis confirmed the presence of barium, titanium and oxygen in the film. The red-shifts of excitonic UV emission peaks were observed in all samples which can be attributed to the stress produced due to lattice distortions. The visible PL emission intensity showed appreciable enhancement with post-deposition annealing.     

Structures and physical properties of sputtered amorphous SiC films

Optical and electrical properties have been measured for amorphous SiC films prepared by rf sputtering in a pure Ar atmosphere with a sintered 6H-SiC target. The absorption edge E₀ determined from the relation of αhΝ = B(hΝ-E₀)² ranged from 1.45 to 1.80 eV depending on the film thickness and the substrate temperature. The room temperature electrical conductivity is in the range of 5.4×10⁻¹¹ and 1.4×10⁻⁵ Ω⁻¹cm⁻¹. The absorption edge decreases and the conductivity increases with increasing film thickness. The absorption edge shifts to shorter wavelengths (blue shift) and the conductivity decreases during annealing below 400‡C for 60 min, whereas the absorption edge shifts to the longer wavelength side (red shift) and the conductivity increases during annealing at 800‡C It is proposed that the two annealing processes cause structural changes in amorphous SiC films, one of which involves removal of defects or voids while the other involves rearrangement or rebonding of the component atoms.     

Effect of tantalum doping on the structural and optical properties of RF magnetron sputtered indium oxide thin films

Tantalum doped indium oxide films are prepared by RF magnetron sputtering technique and the films are annealed in air at 300 °C. The effect of Ta doping on the structural, morphological, and optical properties of the annealed films are studied using techniques like X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), EDX analysis, micro-Raman, UV–visible and photoluminescence spectroscopy and electrical measurements. The XRD patterns present a cubic bixbyite structure for all the films with preferred orientation along the (222) plane. The lattice constant estimation presents a reduction in lattice size with Ta doping. The W–H plot shows a tensile strain for all the films and also indicates the presence of strain induced broadening of the XRD peaks. The Raman spectra present all the characteristic modes of In₂O₃ cubic bixbyite phase. FESEM and AFM images show the uniform and dense distribution of smaller grains in the films. All the films show high transmittance (above 85%) in the 400–900 nm region. Electrical measurement shows a systematic increase of carrier concentration and electrical conductivity with increase in Ta doping concentration. Band gap energy increases with increase in Ta doping concentration. All the films show intense PL emission in the UV region.     

Microstructure and corrosion resistance of room-temperature RF sputtered Ta2O5 thin films

The connection between the chemical corrosion resistance and the microstructure of the Ta₂O₅ thin films prepared at room temperature by a RF magnetron sputtering technique on Si substrates has been investigated. We find that the microstructure of the films changes with different RF sputtering power, and is responsible for the degradation of the corrosion resistance in HF solutions. The deposited films are amorphous and porous when the RF power is low. A preferred orientation toward (200) β-Ta₂O₅ can be observed when the RF power is increased to 150 W. In addition, the films deposited under this condition are dense and are consequently more resistant to the attack of chemicals. AT an RF power of 300 W the corrosion resistance of the films declines due to an increase of the exposed pore surface to the HF solution.     

低温磁控溅射制备CdS薄膜的结构和光学特性

用磁控溅射的方法在透明导电氧化物衬底上制备了CdS薄膜,制备时的衬底温度为30~200℃.X射线衍射测试结果表明在这一条件下制备的CdS薄膜是六角纤锌矿的多晶结构.扫描电子显微镜结果显示薄膜具有较好的晶体质量,这一结论也和拉曼光谱、紫外-可见吸收光谱、光致发光光谱的结果一致.拉曼光谱显示CdS薄膜内部的压应力随着制备温度的提高而增大.     

退火处理对Cu、CuNi薄膜及其热电偶电性能的影响

采用磁控溅射法在单晶硅片基底上制备多个Cu薄膜和CuNi薄膜,对其进行退火处理,分析不同退火温度对薄膜电阻率的影响。结果显示,随着退火温度的升高,两种薄膜的电阻率逐渐减小,且Cu薄膜的电阻率变化较CuNi薄膜更为明显。在镀有SiO2绝缘膜的硅片基底上制备T型(Cu/CuNi)薄膜热电偶,并进行退火处理,对退火前后的热电偶进行静态标定。实验数据表明,T型薄膜热电偶经过退火处理后,灵敏度由退火前38.35μV/℃增大到44.10μV/℃。     

Study on thermal solid-phase crystallization of amorphous ZnO thin films stacked on vanadium-doped ZnO films

Thermal solid-phase crystallization (SPC) of an amorphous ZnO film stacked on a vanadium-doped ZnO (VZO) film was investigated. ZnO films were deposited on 30-nm-thick amorphous VZO films on c-face sapphire substrates at room temperature by RF magnetron sputtering. Stacked film was subsequently calcined at 800 °C in a nitrogen atmosphere. ZnO film grew in an amorphous state up to about 150-nm thick on the amorphous VZO film, but self-orientation occurred in a thicker layer. Any secondary phase such as Zn₂VO₄ was not formed in the case of total film thickness (t_total) ≥100 nm. V concentration decreased by thermal diffusion of V through the ZnO layer from the VZO film, and thereby the formation of secondary phase was effectively avoided. The amorphous ZnO layer was crystallized from highly-aligned initial thin layer of VZO film when t_total ≤200 nm and crystal orientation of the stacked film was superior to single VZO film. However, the c-axis orientation was deteriorated drastically at t_total ≈400 nm due to SPC affected by the tilted regions existed in the as-deposited ZnO film. Therefore, it is suggested that careful selection of ZnO film thickness is necessary to obtain the high-quality ZnO films in this method.