Crystal defects analysis using nano-probe technologies
With the device size shrinking to deep sub-micron region, silicon crystal defects become critical to device parameters. It also brings FA (Failure Analysis) great challenges on timely and exactly identifying the defect by EFA (Electrical Failure Analysis) and PFA (Physical Failure Analysis) methods. In this paper, we report the FA's on the single bit failure of a 6T-SRAM using nano-probe technologies for electrical localization. PFA methods, such as SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope), and chemical etching were performed for failure visualization.
Case study on asymmetric Id measured on MOSFET
With the development of technological process, many Front End Of Line (FEOL) defects are found, and many studies focus on abnormal Id behavior of MOSFETs on SRAM cells. But in this paper a method of how to analyze asymmetric Id measured on a single MOSFET to locate the FEOL defect based on real case analysis is introduced. With studies on cases with asymmetric Id, we have built the corresponding failure mechanism and summarized a decision tree in order to analyze that kind of cases. The decision tree and thinking method are also applied in other cases analysis and shown to be effective.
An Ultrasensitive Analytical Method Based on Chemiluminescence Sensing Electrochemical Parallel Catalytic Reaction Event
An ultrasensitive electrochemiluminescence (ECL) method on the combination of electrochemical parallel catalytic reaction and chemiluminesence signal sensing was proposed for improving ECL analytical characteristics using vanadate(V) as a representative. Vanadate(V) could be electrochemically reduced to generate vanadate(II) which could be chemically oxidized by potassium periodate to regenerate vanadate(V) and give parallel catalytic wave effect. Then, the reduced product of potassium periodate could react with butyl-rhodamine B to emit a sensitive chemiluminescence signal. The chemiluminescence intensity was correlative with vanadate(V) concentration. The investigation on the electrochemical reaction rate constant (k0) confirmed that the speed of electrochemical reaction was faster than that of the subsequent chemiluminescence reaction. The possibility of the combination of electrochemical parallel catalytic reaction with chemiluminescence signal sensing was proved. The similar ECL behaviors could be observed at zirconia nanowires-Nafion modified electrode. Because of the separation and enrichment effect of the modified electrode on vanadate(V), the selectivity and sensitivity was further improved greatly. Based on these findings, a new concept on the combination of electrochemical parallel catalytic reaction and chemiluminesence signal sensing was proposed and an ultrasensitive ECL method for the determination of vanadate(V) was developed at zirconia nanowires-Nafion modified electrode. Under the optimum experimental conditions, the ECL intensity was linear with the concentration of vanadate(V) in the range of 2.0×10−12 mol/L–2.0×10−10 mol/L. The detection limit was 8.0×10−13 mol/L, which was more than 6 orders of magnitude lower than that observed by electrochemical current transduction for electrochemical parallel catalytic reaction at zirconia nanowires-Nafion modified electrode.