This paper mainly focuses on solving the low yield problem for lateral phase change random access memory with a fully confined phase change material node. Improper over-etching and bad step-coverage of physical vapor ...This paper mainly focuses on solving the low yield problem for lateral phase change random access memory with a fully confined phase change material node. Improper over-etching and bad step-coverage of physical vapor deposition were the main reasons for the poor contact quality, which leads to the low yield problem. Process improvement was carried out to better control over-etching within 10 nm. Atomic layer deposition process was used to replace physical vapor deposition to guarantee good step coverage. Contrasting cross-sectional photos taken by scanning electron microscopy showed great improvement in contact quality. The atom layer deposition process was demonstrated to have good prospects in nano-contact for phase change memory application.展开更多
The emission microscopy （EMMI） test is proposed as an effective method to control the polysilicon over-etching time of advanced CMOS processing combined with a novel test structure, named a poly-edge structure. From...The emission microscopy （EMMI） test is proposed as an effective method to control the polysilicon over-etching time of advanced CMOS processing combined with a novel test structure, named a poly-edge structure. From the values of the breakdown voltage （Vbd） of MOS capacitors （poly-edge structure） ,it was observed that,with for the initial polysilicon etching-time, almost all capacitors in one wafer failed under the initial failure model. With the increase of polysilicon over-etching time, the number of the initial failure capacitors decreased. Finally, no initial failure capacitors were observed after the polysilicon over-etching time was increased by 30s. The breakdown samples with the initial failure model and intrinsic failure model underwent EMMI tests. The EMMI test results show that the initial failure of capacitors with poly-edge structures was due to the bridging effect between the silicon substrate and the polysilicon gate caused by the residual polysilicon in the ditch between the shallow-trench isolation region and the active area, which will short the polysilicon gate with silicon substrate after the silicide process.展开更多
Diffraction effects will bring about more difficulties in actuating resonators,which are electrostatically actuated ones with sub-micrometer or nanometer dimensions,and in detecting the frequency of the resonator by o...Diffraction effects will bring about more difficulties in actuating resonators,which are electrostatically actuated ones with sub-micrometer or nanometer dimensions,and in detecting the frequency of the resonator by optical detection.To avoid the effects of diffraction,a new type of nanoelectromechanical systems（NEMS） resonators is fabricated and actuated to oscillate.As a comparison,a doubly clamped silicon beam is also fabricated and studied.The smallest width and thickness of the resonators are 180 and 200 nm,respectively.The mechanical oscillation responses of these two kinds of resonators are studied experimentally.Results show that the resonant frequencies are from 6.8 to 20 MHz,much lower than the theoretical values.Based on the simulation,it is found that over-etching is one of the important factors which results in lower frequencies than the theoretical values.It is also found that the difference between resonance frequencies of two types of resonators decreases with the increase in beam length.The quality factor is improved greatly by lowering the pressure in the sample chamber at room temperature.展开更多
基金supported by the National Basic Research Program of China(No.2011CB922103)the National Natural Science Foundation of China(Nos.61376420,61404126,A040203)the Science and Technology Project of Shenzhen(No.JCYJ20140509172609175)
文摘This paper mainly focuses on solving the low yield problem for lateral phase change random access memory with a fully confined phase change material node. Improper over-etching and bad step-coverage of physical vapor deposition were the main reasons for the poor contact quality, which leads to the low yield problem. Process improvement was carried out to better control over-etching within 10 nm. Atomic layer deposition process was used to replace physical vapor deposition to guarantee good step coverage. Contrasting cross-sectional photos taken by scanning electron microscopy showed great improvement in contact quality. The atom layer deposition process was demonstrated to have good prospects in nano-contact for phase change memory application.
文摘The emission microscopy （EMMI） test is proposed as an effective method to control the polysilicon over-etching time of advanced CMOS processing combined with a novel test structure, named a poly-edge structure. From the values of the breakdown voltage （Vbd） of MOS capacitors （poly-edge structure） ,it was observed that,with for the initial polysilicon etching-time, almost all capacitors in one wafer failed under the initial failure model. With the increase of polysilicon over-etching time, the number of the initial failure capacitors decreased. Finally, no initial failure capacitors were observed after the polysilicon over-etching time was increased by 30s. The breakdown samples with the initial failure model and intrinsic failure model underwent EMMI tests. The EMMI test results show that the initial failure of capacitors with poly-edge structures was due to the bridging effect between the silicon substrate and the polysilicon gate caused by the residual polysilicon in the ditch between the shallow-trench isolation region and the active area, which will short the polysilicon gate with silicon substrate after the silicide process.
基金The National High Technology Research and Development Program of China(863 Program)(No.2007AA04Z301)
文摘Diffraction effects will bring about more difficulties in actuating resonators,which are electrostatically actuated ones with sub-micrometer or nanometer dimensions,and in detecting the frequency of the resonator by optical detection.To avoid the effects of diffraction,a new type of nanoelectromechanical systems（NEMS） resonators is fabricated and actuated to oscillate.As a comparison,a doubly clamped silicon beam is also fabricated and studied.The smallest width and thickness of the resonators are 180 and 200 nm,respectively.The mechanical oscillation responses of these two kinds of resonators are studied experimentally.Results show that the resonant frequencies are from 6.8 to 20 MHz,much lower than the theoretical values.Based on the simulation,it is found that over-etching is one of the important factors which results in lower frequencies than the theoretical values.It is also found that the difference between resonance frequencies of two types of resonators decreases with the increase in beam length.The quality factor is improved greatly by lowering the pressure in the sample chamber at room temperature.
