Electron-beam radiation induced degradation of silicon nitride and its impact to semiconductor failure analysis by TEM

By in-situ transmission electron microscopy (TEM), we performed a detailed study on the electron-beam radiation damage to nanostructured silicon nitride thin-film process layers in a typical semiconductor NVM device. It was found that high-dose electron-beam radiation at 200 kV led to rapid degradation of silicon nitride process layers, i.e. thin-downing of nanostructured silicon nitride, inter-diffusion of O and N, the formation of bubble-like defects and segregation of N at neighbouring interfaces. Further detailed analysis revealed that radiation-induced modification in the microstructure and chemical composition of silicon nitride layers could be ascribed to the electron radiation induced knock-on damage and ionization damage. The radiation enhanced diffusion (RED) accounted for the continuous thin-down of the nitride process layer and the formation of bubble-like defects in thick nitride spacer process layers. The work well demonstrated the electron-beam sensitivity of nanostructured silicon nitride materials in the semiconductor devices, and thus may give useful information about electron-dose control during TEM failure analysis of the semiconductor devices containing nanostructured silicon nitride process layers

The overview of the impacts of electron radiation on semiconductor failure analysis by SEM, FIB and TEM

The paper briefly overviewed electron-beam radiation damage and its impacts on physical failure analysis by SEM, FIB and TEM. Based on our electron radiation study on some typical electron-beam sensitive materials, we discussed some interesting results associated with electron radiation damage to Lk/ULK, silicon nitride and CoFeB thin film materials in semiconductor and MRAM devices. The details included radiation induced microstructure changes., material diffusion and phase transformation. The underlying mechanism was also briefly discussed for electron radiation damage to different materials

Robo-Erectus: Team Description 2005 1 Robo-Erectus: Team Description 2005

Abstract. This paper provides a brief description of Robo-Erectus (RE), the humanoid developed in the Advanced Robotics and Intelligent Control Centre of Singapore Polytechnic that will participate in the humanoid league of RoboCup 2005. The project to develop a low-cost humanoid platform is presented. The mechanical structure of Robo-Erectus and the evolution of its various models is presented. The development of its control systems and the planning of itsdynamically stable walking and kicking gait of the robot is also described.

Electron radiation-induced material diffusion and nanocrystallization in nanostructured amorphous CoFeB thin film

Transmission electron microscopy (TEM) is widely used for physical characterization of CoFeB based magnetic tunneling junctions (MTJ) with its atomic-scale resolution. However, highly energetic electron radiation during TEM analysis may cause phase and microstructure modification of CoFeB and its associated MTJ layers. It is the intention of this work to address the issues of the electron-beam sensitivity of CoFeB material. With in-situ TEM, we investigated the electron beam radiation-induced material diffusion and the nanocrystallization behaviors in nanostructured amorphous CowFexByOz/Co60Fe20B20/SiO2 thin films. It was found that electron radiation with different electron dose led to massive diffusion of Co, Fe, B and O atoms across the whole thin film layers, which directly resulted in the modification of the phase and composition of the thin film layers, i.e. the oxidation of Co, Fe, B with O diffusion and the formation of pure Si phase from SiO2. Two stages of material diffusion were observed. While Stage-I material diffusion proceeded with a high diffusion speed, Stage-II had a relatively low diffusion rate accompanying with the nanocrystallization at the bottom of the CoFeB layer. A detailed kinetic study by in-situ TEM revealed the electron-beam radiation induced massive diffusion was a non-thermal process, and the underlying driving force arose from radiation-enhanced diffusion (RED) effects. Nanocrystallization during Stage-II electron-radiation experiment showed unique phase transformation phenomena, repeated nanocrystallization, amorphization, and nanocrystallization processes in the sequence before a stable grain growth could be achieved. A detailed TEM analysis revealed that RED-enhanced B diffusion was responsible for such unique repeated phase transformation processes. B diffusion and the associated structure distortion and the local short-range re-ordering may also account for the phase transformation from fcc-CoxFe23-xB6 to B-rich orthorhombic- CoxFe3-xB phase

Effects of once-weekly exenatide on cardiovascular outcomes in type 2 diabetes

BACKGROUND: The cardiovascular effects of adding once-weekly treatment with exenatide to usual care in patients with type 2 diabetes are unknown. METHODS: We randomly assigned patients with type 2 diabetes, with or without previous cardiovascular disease, to receive subcutaneous injections of extended-release exenatide at a dose of 2 mg or matching placebo once weekly. The primary composite outcome was the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The coprimary hypotheses were that exenatide, administered once weekly, would be noninferior to placebo with respect to safety and superior to placebo with respect to efficacy. RESULTS: In all, 14,752 patients (of whom 10,782 [73.1%] had previous cardiovascular disease) were followed for a median of 3.2 years (interquartile range, 2.2 to 4.4). A primary composite outcome event occurred in 839 of 7356 patients (11.4%; 3.7 events per 100 person-years) in the exenatide group and in 905 of 7396 patients (12.2%; 4.0 events per 100 person-years) in the placebo group (hazard ratio, 0.91; 95% confidence interval [CI], 0.83 to 1.00), with the intention-to-treat analysis indicating that exenatide, administered once weekly, was noninferior to placebo with respect to safety (P<0.001 for noninferiority) but was not superior to placebo with respect to efficacy (P=0.06 for superiority). The rates of death from cardiovascular causes, fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, hospitalization for heart failure, and hospitalization for acute coronary syndrome, and the incidence of acute pancreatitis, pancreatic cancer, medullary thyroid carcinoma, and serious adverse events did not differ significantly between the two groups. CONCLUSIONS: Among patients with type 2 diabetes with or without previous cardiovascular disease, the incidence of major adverse cardiovascular events did not differ significantly between patients who received exenatide and those who received placebo