Low-resistance polysilicon process in contact application for high density devices

For the lowest resistance, it is required to have the epitaxial silicon contact between the silicon plug and the substrate and good step coverage at the high aspect-ratio contact holes, simultaneously. In this work, a double polysilicon (DPS) deposition technique was proposed for the requirements. The first, thin silicon layer is deposited in a single-wafer process chamber with an in-situ H₂-RTP (rapid thermal process) treatment for the epitaxial contact, and the second silicon layer is formed in a batch-type furnace for good step coverage. From chain resistance, Kelvin R_c, and current-voltage (I–V) measurement, the DPS process meets both low resistance and good uniformity, so that it suggests a breakthrough in the small-sized, semiconductor device application.     

基于负温度系数的多晶硅电阻电热激励/压阻检测微桥谐振器的新型红外探测器

报道了一种基于负电阻温度系数的多晶硅电阻电热激励/压阻检测SiO 2/Si3N4/SixNy微桥谐振器的新型红外探测器.微桥谐振器吸收的红外辐射引起微桥温度升高,激励电阻和检测电桥的阻值减小,使得恒定激励电压作用下激励电阻的静态功率和惠斯登电桥的焦耳热增加,等效于增加了辐射在微桥谐振器上的红外辐射.初步的实验证实了该方案的可行性.     

采用多晶硅制造高速光导开关(Au:Si-PCSS)的研究

首次报导采用多晶硅制造高速光导开关取得缩短寿命至10ns以下并改善光控灵敏度。分析了原理并涉及工艺等问题。文中对GaAs与Si两种材料的PCSS作了比较。     

The oxidation of titanium silicide

This paper investigates the morphology changes that occur with the oxidation of a ti-tanium silicide—polysilicon system. These changes were studied as a function of poly-silicon doping and silicide formation parameters. Emphasis was placed on transmission electron microscopy studies of the samples by planar and cross sectional techniques. Various surface analysis methods have also been used to characterize the films. This study helps to define the possible use and shortcomings of a self aligned titanium silicide insulator. The results show that varying quality insulators result, dependent largely on the initial conditions of the titanium silicide. After oxidation the Auger and TEM anal-ysis show that in all cases some form of silicon dioxide was created, but typically a considerable amount of titanium oxide was also present. For instance, it was apparent that more titanium oxide formed on the samples RTA’ed for 1 min at 700° C than the 5 min at 800° C and considerably more on the arsenic doped sample than the boron doped. The silicide also had morphology changes as the result of the oxidation. There was a phase change from the C49 to C54 phase for the 1 min at 700° C samples as would be expected at the time and temperature of the oxidation. There also was a sig-nificant amount of agglomeration and epitaxial growth observed. Further work is re-quired to completely characterize these phenomena.     

Improvement of the field emission characteristics of an oxidized porous polysilicon using annealed Pt/Ti surface emitter electrode

The field emission characteristics of an oxidized porous polysilicon were investigated with different annealing temperatures. Pt/Ti, Ir, and Au/NiCr were used as surface emitter electrodes, and Pt/Ti emitter showed highly efficient and stable electron emission characteristic compared with the conventional Au/NiCr electrode. Thin Ti layer played an important role in promotion of adhesion of Pt to SiO₂ surface and uniform distribution of electric field on the OPPS surface. Additionally, the Ti layer efficiently blocked the diffusion of emitter metal, which resulted in more reliable emission characteristics. Pt/Ti emitter annealed at 350 °C/1 h showed the highest efficiency of 3.36% at V_ps=16 V, which resulted from the improvement of interfacial contact characteristics of thin emitter metal to an oxidized porous polysilicon. Annealing above 400 °C showed that Pt/Ti and Ir emitter electrode were thermally more stable than Au/NiCr emitter.     

LPCVD系统淀积多晶硅薄膜的发雾分析

叙述了采用LPCVD系统淀积多晶硅薄膜的机理,分析了在淀积多晶硅薄膜过程中引起发雾的因素,指出了保持LPCVD系统的洁净能有效消除在淀积多晶硅薄膜过程中出现的发雾现象.     

Fatigue damage evolution in silicon films for micromechanical applications

In this paper we examine the conditions for surface topography evolution and crack growth/fracture during the cyclic actuation of polysilicon microelectromechanical systems (MEMS) structures. The surface topography evolution that occurs during cyclic fatigue is shown to be stressassisted and may be predicted by linear perturbation analyses. The conditions for crack growth (due to pre-existing or nucleated cracks) are also examined within the framework of linear elastic fracture mechanics. Within this framework, we consider pre-existing cracks in the topical SiO₂ layer that forms on the Si substrate in the absence of passivation. The thickening of the SiO₂ that is normally observed during cyclic actuation of Si MEMS structures is shown to increase the possibility of stable crack growth by stress corrosion cracking prior to the onset of unstable crack growth in the SiO₂ and Si layers. Finally, the implications of the results are discussed for the prediction of fatigue damage in silicon MEMS structures.     

多晶硅薄膜晶体管RPI模型的直流参数提取

多晶硅薄膜晶体管(TFT)在有源液晶显示器中的应用充分显示了它的性能优点。对多晶硅TFT进行模型分析和参数提取是理解多晶硅TFT工作原理和指导制备的有效途径。归纳并讨论了多晶硅薄膜晶体管RPI模型直流参数的提取策略。此参数提取步骤简单,并能准确地提取所有工作区的基本直流参数,如阈值电压、漏源区串联寄生电阻、有效沟道长度、迁移率等。参数提取的方法将为RPI模型的电路仿真提供有益的参考。最后,提出了改进RPI模型参数提取策略的方向,包括提高泄漏电流参数、迁移率参数的准确度等。     

超高速VLSI中多晶硅发射极晶体管串联电阻的测量

本文对目前流行的测量晶体管串联电阻的常规方法进行了理论分析和实验验证，结果表明，用常规方法测量多晶硅发射极晶体管串联电阻的误差很大。     

Characteristics of thin film transistors fabricated in polysilicon films deposited by plasma enhanced chemical vapor deposition

Thin-film transistors (TFTs) fabricated in polysilicon films deposited by plasma enhanced chemical vapor deposition (PECVD) were characterized. The transistors were fabricated using a low temperature process (i.e., <- 700° C). The characteristics of the devices were found to improve as the deposition temperature of the polysilicon film increased. The best characteristics (μ _FE of 15 cm²/V _s andV _TH of 2.2V) were measured in the devices fabricated in the film deposited at 700° C. The devices fabricated in the PECVD polysilicon films were compared to those fabricated in polysilicon films deposited by thermal CVD in the same reactor in order to decouple the effect of the plasma. A coplanar electrode structure TFT with adequate characteristics (μ _FE of 8 cm²/V _s) was also demonstrated in the PECVD polysilicon films.