局部增强压焊块铝层厚度的工艺方法

针对目前铜线封装对芯片压焊块的铝层厚度要求较高的问题,通过改进芯片制造工艺流程,对芯片内部压焊块的铝层进行单独地加厚。以便同时满足芯片封装厂采用铜线打线和芯片制造厂金属刻蚀工艺难易的要求。做法为,在钝化层刻蚀完成后,再生长一层足够厚的金属层,进行钝化层反版的光刻以及湿法刻蚀,只保留下压焊块区域的金属层,此时压焊块区域就...     

Crystalline silicon surface passivation by amorphous silicon carbide films

This article reviews the surface passivation of n- and p-type crystalline silicon by hydrogenated amorphous silicon carbide films, which provide surface recombination velocities in the range of 10 cm s⁻¹. Films are deposited by plasma-enhanced chemical vapor deposition from a silane/methane plasma. We determine the passivation quality measuring the injection level (Δn)-dependent lifetime (τ_eff(Δn)) by the quasi-steady-state photoconductance technique. We analyze the experimental τ_eff(Δn)-curves using a physical model based on an insulator/semiconductor structure and an automatic fitting routine to calculate physical parameters like the fundamental recombination velocities of electrons and holes and the fixed charge created in the film. In this way, we get a deeper insight into the effect of the deposition temperature, the gas flow ratio, the doping density of the substrate and the film thickness on surface passivation quality.     

Investigation of various surface passivation schemes for silicon solar cells

In this work, we have investigated three different surface passivation technologies: classical thermal oxidation (CTO), rapid thermal oxidation (RTO) and silicon nitride by plasma enhanced chemical vapor deposition (PECVD). Eight different passivation properties including SiO₂/SiN_x stacks on phosphorus diffused (100 and 40 Ω/Sq) and non-diffused 1 Ω cm FZ silicon were compared. Both types of SiO₂ layers, CTO and RTO, yield a higher effective lifetime on the emitter surface than on the non-diffused surface. For the SiN_x layers the situation is reverted. On the other hand, with SiO₂/SiN_x stacks high lifetimes are obtained not only non-diffused surface but also on the diffused surface. Thus, we have chosen the RTO/SiN_x stack layers as front and rear surface passivation in solar cells, which passivate relatively good on the surface and has very low-weighted reflection. On planar cells passivated with RTO/SiN_x a very high V_oc of 675.6 mV and a J_sc of 35.1 mA/cm² was achieved. Compared to a planar cell using CTO the efficiency of RTO/SiN_x cell is 0.8% higher (4.5% relative). It can be concluded that the RTO/SiN_x layers are the optimal passivation for the front and rear surface. On the other hand, for textured cells, the J_sc and FF of RTO/SiN_x cells are lower than those of CTO cells. The main reasons of these J_sc and FF losses were also discussed systematically.     

锅炉清洗工作技术方案的制定

本文对锅炉清洗的准备、清洗和钝化等全过程所涉及内容进行一些经验总结，并提出具体技术要求。     

Damage to n-MOSFETs from electrical stress Relationship to processing damage and impact on device reliability

The study reported herein examines and compares damage to n-channel and p-channel metal-oxide-silicon field-effect transistors (MOSFETs) from direct current (d.c.) and alternating current (a.c.) electrical stresses as well as the relationship of this damage to plasma processing damage in MOSFETs. The lightly-doped drain (LDD) MOSFETs used are of 0.5 μm channel length and with a 90 Å thick thermally grown gate oxide fabricated using a full flow CMOS process up to and including metal-1 processes and post-metallization annealing (PMA). The damage to MOSFETs is assessed using transistor parameter characterization and charge-to-breakdown measurements on the gate oxide. It is found that manifestations of d.c. stress-induced damage and a.c. stress-induced damage to transistors are fairly similar in that both forms of damage are passivated by PMA and are reactivated by a subsequent d.c. electrical stress. However, a.c. stress-induced damage is observed to occur at much lower electric fields across the gate oxide than those necessary for d.c. stress-induced damage to be significant. This is attributed to a.c. currents, caused by carrier hopping, occurring at relatively low electric fields. One implication of our results is that plasma-charging damage, often attributed to d.c. electrical stress alone, may comprise an a.c. electrical stress component too.     

Electrochemical deposition of poly(o-anisidine) and polypyrrole at octadecanethiol coated gold electrodes

The o-anisidine and pyrrole have been polymerized by the electrochemical oxidation of monomers on gold electrodes, covered with self-assembled monolayers. The obtained polymer–monolayer systems have been investigated by cyclic voltammetry in aqueous supporting electrolyte solutions containing K₄Fe(CN)₆ and Ru(NH₃)₆Cl₃. The deposition of conducting polymers strongly depends on the integrity of a monolayer. In the case of a large number of SAM defects, the polymerization of o-anisidine and pyrrole leads to the formation of nuclei of the conducting polymer in the insulating matrix of the thiol monolayer. When the polymer is in the conducting (oxidized) form, the nuclei act as an array of microelectrodes. The polarogram-shaped voltammograms obtained for K₄Fe(CN)₆ confirm the hemispherical diffusion of redox species to the polymer nuclei. When the polymer is in the non-conducting (reduced) form, the polymer–octadecanethiol layer blocks the redox processes on the electrode. The exponential-type CV curves observed for Ru(NH₃)₆Cl₃, when the polymer is in its non-conducting state, can be assigned to the tunnelling of electrons through the passivating layer. The use of monolayers with a low number of defects influences the mechanism of polymer growth. Thus, the polypyrrole grows on the layer of thiols, and the poly(o-anisidine) forms polymer nuclei.     

Effect of nanocrystalline grain size on the electrochemical and corrosion behavior of nickel

Nanocrystalline nickel of different grain sizes (8–28 nm) was produced by electrodeposition using Watt's bath. Saccharine addition to the bath and pulsed current deposition were effective in lowering the grain size of the deposits. The grain size and microstrain of deposits was determined by X-ray diffraction analysis. The microhardness of nanocrystalline Ni ranged between 572 and 724 kg/mm². The electrochemical behavior of nanocrystalline Ni was evaluated in 1 mol/l H₂SO₄ and compared with that of coarse-grained nickel. All the nickel samples exhibited active–passive potentiodynamic polarization behavior. The zero current potential, passive current density and breakdown potential generally increased with decrease in grain size. The increased passive current density for nanocrystalline nickel confirmed the defective nature of passive film that forms on nanocrystalline nickel. The tendency for localized corrosion was lower in case of nanocrystalline nickel as indicated by increased breakdown potential. Tafel and linear polarization tests revealed that the corrosion rate of freshly exposed surfaces of Ni decreased with grain size, thereby indicating greater hindrance to anodic dissolution in nanocrystalline Ni. The magnitude of compressive microstrain in the Ni deposits increased with decrease in grain size.     

铬不锈钢混合酸钝化工艺及参数优化

主要对铬不锈钢以H2SO4、Na NO3为原料的混合酸钝化工艺进行试验,并在此基础上对钝化槽的工艺、参数进行讨论。     

Undercoordinated Pb2+ defects passivation via tetramethoxysilane-modified for efficient and stable perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have developed rapidly in recent years, and the instability limits its commercialization. Non-radiative recombination caused by defects and water stability affect the device stability. Here we introduce an organic silane additive, tetramethoxysilane (TMOS), which can reduce the non-radiative recombination and prevent the water erosion. The methoxy group in TMOS can combine with Pb²⁺ of perovskite to passivate undercoordinated Pb²⁺ defects and reduce non-radiative recombination. Under a certain humidity, the hydrolyzed product SiO₂ can occupy the grain boundary sites to prevent the erosion of water molecules, slow down the degradation of perovskite, and improve the crystal phase stability of perovskite. The PCE of the device increases from 17.13% to 20.12%. After 400 h at 50% relative humidity (RH), the PSC with 2% TMOS can maintain the efficiency of 90%, while the efficiency of the control group quickly dropped to only 70% of the initial.     

Encapsulation of organic light-emitting devices by means of photopolymerized polyacrylate films

For encapsulation of organic light-emitting devices (OLEDs) built on glass substrate, photopolymerizable blend consists of pentaerythritol triacrylate (PETIA) and HSP188 (photoinitiator) was spin-coated onto an OLED and then cured to form a cross-linked passivation layer. The electroluminescence (EL) and the rate of degradation were examined to compare the electrical and the emissive properties of the device before and after forming the passivation layer. In this case, wet process encapsulation, which did not influence the EL characteristic of the device, enhanced the lifetime of the device in air.