真空退火对低频PECVD氮化硅薄膜性能的影响

研究了真空退火温度对不同流量比工艺参数下PECVD氮化硅薄膜性能的影响,测试了退火后氮化硅薄膜厚度、折射率以及在氢氟酸中的腐蚀速率。结果表明,退火后氮化硅薄膜厚度及折射率变化与薄膜沉积工艺条件有关,而薄膜在氢氟酸中的腐蚀速率在退火后大大降低。结合退火前后氮化硅薄膜的红外透射谱对以上测试结果进行了讨论。     

管式PECVD射频功率对氮化硅薄膜性能的影响

氮化硅薄膜作为传统的晶体硅太阳电池钝化减反膜,其性能的变化直接影响电池的转化效率。通过改变管式PECVD的射频功率,制备了不同膜厚和折射率的氮化硅薄膜,并分别进行了薄膜致密性以及硅片镀膜后少子寿命的测试。实验及测试结果表明,改变PECVD的射频功率对氮化硅薄膜的沉积速率及其薄膜的性能有重要影响。     

氮化硅薄膜的PECVD生长及其性能研究

采用ＰＥＣＶＤ法，反应温度为２５０℃，反应气体为ＮＨ３，ＳｉＨ４，在抛光硅片上沉积０．２～０．４μｍ厚的氮化硅薄膜。对这种Ｓｉ３Ｎ４薄膜的光学性能和电学性能进行了测试，其光学折射率为１．８７５，电阻率及击穿场强分别为８×１０１６Ω·ｃｍ及１×１０７Ｖ／ｃｍ，并用ＦＴＩＲ谱分析了薄膜的化学结构。     

PECVD制备氮化硅薄膜的研究

采用PECVD法制备了氮化硅薄膜,探讨了沉积参数对氮化硅薄膜折射率的影响和衬底温度对氮化硅薄膜形貌和成分的影响规律。结果表明,不同的NH3流量可改变反应腔体内的氮硅比,对氮化硅的折射率,即减反射性能影响较大;衬底温度是影响氮化硅薄膜形貌和成分的主要因素;在衬底温度达到400℃时,形成了白色团状或岛状的氮化硅膜。     

流量及温度对低频PECVD氮化硅薄膜性能的影响

研究了低频等离子增强化学气相沉积(LF-PECVD)工艺中气体流量比和衬底温度对氮化硅薄膜折射率、密度及应力的影响规律,同时测试了薄膜的红外光谱以分析不同条件对薄膜成分的影响.结果表明,低频氮化硅薄膜折射率主要受薄膜内硅氮元素比的影响,其次是薄膜密度的影响.前者主要由硅烷/氨气反应气体流量比决定,而后者主要由衬底温度决定;低频氮化硅薄膜应力大致与密度成正比关系.此外,PECVD工艺所制备氮化硅薄膜都含有相当数量的氢元素,而衬底温度是薄膜内氢含量的决定因素.     

低应力PECVD氮化硅薄膜的制备

研究了等离子增强化学气相淀积(PECVD)工艺中射频条件(功率和频率)对氮化硅薄膜应力的影响.对于不同射频条件下薄膜的测试结果表明:低频(LF)时氮化硅薄膜处于压应力,高频(HF)时处于张应力,且相同功率时低频的沉积速率和应力分别为高频时的两倍左右;在此基础上采用不同高低频时间比的混频工艺实现了对氮化硅薄膜应力的调控,且在高低频时间比为5:1时获得了应力仅为10 MVa的极低应力氮化硅薄膜.     

多晶硅太阳电池PECVD氮化硅钝化工艺的研究

介绍等离子体化学气相淀积(PECVD)制备减反射钝化膜。将PECVD设备运用于太阳电池生产线上,发现通过PECVD设备可以对多晶硅太阳电池有很好的钝化效果。分析PECVD对多晶硅太阳电池钝化机理。     

氮化硅支撑层薄膜的PECVD法制备及性能研究

采用等离子体增强化学气相沉积法(PECVD),在二氧化硅衬底(SiO2/Si(100))上成功制备了用于非致冷红外焦平面阵列微桥结构支撑层的氮化硅薄膜.采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)及原子力显微镜(AFM)研究了薄膜的微观结构和表面形貌;分别采用台阶仪、薄膜应力分布测试仪和快速退火炉等手段测试了薄膜的厚度均匀性,应力大小和耐温性能等参数.结果表明,制备氮化硅薄膜为非晶态,含有少量的氢,主要表现为Si-N键合;薄膜表面平整、致密,厚度不均匀性小于5%,具有107Pa的较低压应力,耐温性能较好.     

低应力PECVD氮化硅薄膜工艺探讨

介绍了一种掺氦的等离子增强化学气相淀积（ＰＥＣＶＤ）氮化硅薄膜工艺技术,可调控氮化硅薄膜的应力,从而在较低的射频功率下生长低应力的氮化硅薄膜。文中对其机理作了初步的探讨。所生长的氮化硅薄膜的折射率和腐蚀速率没有明显变化,对器件,尤其是对砷化镓异质结器件几乎没有应力损伤。     

Physical properties of memory quality PECVD silicon nitride

Memory-quality silicon nitride has been deposited using plasma-enhanced chemical vapor deposition (PECVD). Film composition was varied by controlling the nitrogen concentration of the reactant gases. The effects of the source and content of the nitriding agent on the physical properties of the film were studied using ellipsometry and ultraviolet (UV), fourier transform infrared (FTIR) and Auger electron spectroscopy. Refractive index of the films varied from 1.77 to 1.95 corresponding to Si/N ratios of 0.75 to 1.03. Ultraviolet spectroscopy yielded band edge values of 4.9 to 2.2 eV depending on the Si/N ratio. Window size, endurance and retention performance is comparable to that reported for both atmospheric- and low-pressure chemical vapor deposited films. A strong correlation between the Si-H bond concentration and the memory performance was observed. Although some excess silicon in the film is needed for memory operation in a metal-nitride-oxide-silicon (MNOS) structure, excessive amounts result in low breakdown fields, small memory windows and poor retention characteristics. This work was supported by a grant from the National Science Foundation.     

A CFD model for the PECVD of silicon nitride

This work describes the methodology used to develop a computational fluid dynamic (CFD) model for the plasma-enhanced chemical vapor deposition (PECVD) of silicon nitride (SiN_x) for an N ₂SiH₄-NH₃ process. The model has been developed for the Applied Materials Precision 5000 single-wafer reactor, and has the reaction chamber geometry, thermal characteristics, and reactant delivery system incorporated into it. A one-dimensional simulator was used to investigate the initial reaction mechanisms. An experimental design was carried out using physically-based transformations in order to provide model calibration data. The reaction rates were then optimized using the experimental data and the one-dimensional simulator in conjunction with a nonlinear optimizer. A two-dimensional model has been developed using FLUENT, a commercially available computational fluid dynamics program. A simplified plasma modeling technique has been developed which permits the incorporation of electron-initiated reactions generated by the radio-frequency (RF) plasma. This model provides the capability to predict the film composition and deposition rates across the substrate surface. A comparison to the nominal point experimental data has been performed and is reported as well     

Processing and characterisation of PECVD silicon nitride films

Amorphous Si-N films are synthesised from an NH₃/SiH₄ gas mixture by plasma-enhanced chemical vapour deposition (PECVD) at fixed radio frequency (13.56 MHz) and total gas pressure (34 ± 4 Torr). The variable process parameters and their ranges are: (i) substrate temperature, 200–400°C; (ii) RF power density, 0.08–0.35 W cm⁻²; (iii) NH₃/SiH₄ flow ratio, 40:400–40: 1200 ml min⁻¹. Fundamental properties of the Si-N films are characterised through elemental composition, chemical speciation, optical and electrical properties, all of which are dependent on the process parameters.     

Real-time multivariable control of PECVD silicon nitride filmproperties

This paper reports on the application of quadrupole mass spectrometry (QMS) sensing to real-time multivariable control of film properties in a plasma-enhanced CVD silicon nitride process. Process variables believed to be most important to film deposition are defined (i.e., disilane pressure, triaminosilane pressure, and dc bias voltage) and their responses to system inputs are modeled experimentally. Then, a real-time controller uses this information to manipulate the process variables and hence film performance in real time during film deposition. The relationships between gas concentrations and film performance are shown explicitly where the controller was used to drive the concentrations to constant setpoints. Also, an experiment investigating the effects of an out-of-calibration mass flow controller demonstrates the compensating ability of the real-time controller. The results indicate that in situ sensor-based control using quadrupole mass spectrometry can significantly assist in optimizing film properties, reducing drift during a run, reducing run-to-run drift, creating a better understanding of the process, and making the system tolerant to disturbances     

Characterization and comparison of PECVD silicon nitride and silicon oxynitride dielectric for MIM capacitors

In this letter, we report on the electrical characteristic and the comparison of the metal-insulator-metal (MIM) capacitors with PECVD silicon nitride (SiN) and silicon oxynitride (SiON). Both capacitors are found to exhibit low leakage and high breakdown field strength, as well as absence of dispersive behavior, good linearity, and comparable quality factor behaviors.     

视频电话的RTP协议具体实现的研究

首先介绍RTP协议的内容.在具体实现过程中,针对因特网传输丢包率比较高的问题,讨论了采取IP包分割技术、纠错处理、缓冲处理等措施,确保语音和视频图像的平滑.     

Optical properties of silicon rich silicon oxides obtained by PECVD

In this work optical properties of SiO_X (0<X<2) layers obtained by plasma enhanced chemical vapor deposition are studied. Infrared spectra and refractive index dependences with the reactant gases flow ratio R are explained for as deposited, aged and thermally treated samples in the R range from 9.17 to 110. Variations are found to be influenced mainly by sample stoichiometry, density and Si-OH bonds concentration.     

GStreamer RTP插件的改进及应用

论文介绍了GStreamer基本概念,分析了RTP插件原理,并在已有uctimclient、Open IMS核构成的开源多媒体系统基础上,对G711音频RTP插件进行了改进,引入SRTP功能,实现VOIP端到端音频数据机密性、完整性保护功能.     

Passivation of GaAs FET's with PECVD silicon nitride films ofdifferent stress states

The passivation of GaAs MESFETs with plasma-enhanced chemical-vapor-deposited (PECVD) silicon nitride films of both compressive and tensile stress is reported. Elastic stresses included in GaAs following nitride passivation can produce piezoelectric charge density, which results in a shift of MESFET characteristics. The shift of MESFET parameters due to passivation was found to be dependent on gate orientation. The experiments show that nitride of tensile stress is preferable for MESFETS with [011-bar] oriented gates. The shifts in V_TH,I_DSS, and G_M of the devices before and after nitride passivation are less than 5% if the nitride of appropriate stress states are used for passivation. The breakdown voltage of the MESFETs after nitride deposition was also studied. It is found that the process with higher hydrogen incorporation tends to reduce the surface oxide and increase the breakdown voltage after nitride deposition. In addition, the passivation of double-channel HEMTs is reported for the first time     

Effects of nitrogen and argon as carrier gases and annealing ambients on the physical properties of PECVD silicon nitride

Deposition of memory quality plasma-enhanced chemically vapor deposited silicon nitride and post-deposition modification by annealing using argon and nitrogen for carrier gases and annealing ambients have been studied. Although similar memory performance can be achieved, the deposition power and NH₃/SiH₄ ratio required to do so are functions of the carrier gas used since nitrogen actively participates in the deposition process. Fourier transform infrared, ultraviolet and Auger data reveal that materials deposited with the two gases have similar physical properties although argon films are less dense and lose hydrogen at a higher rate when subjected to annealing. Post-deposition annealing can be used to enhance memory properties of the material provided that the anneal is accomplished at 475°C for 30 minutes. However, enhancement of memory performance by annealling occurs only if the nitride has been deposited using optimum deposition parameters. When annealing is performed in nitrogen. Auger data suggest that nitrogen can be supplied to, or removed from, the material depending on the anneal temperature.