Improved Endurance of Ferroelectric Hf0.5Zr0.5O2 Using Laminated-Structure Interlayer.

In this article, the endurance characteristic of the TiN/HZO/TiN capacitor was improved by the laminated structure of a ferroelectric Hf0.5Zr0.5O2 thin film. Altering the HZO deposition ratio, the laminated-structure interlayer was formed in the middle of the HZO film. Although small remanent polarization reduction was observed in the capacitor with a laminated structure, the endurance characteristic was improved by two orders of magnitude (from 106 to 108 cycles). Moreover, the leakage current of the TiN/HZO/TiN capacitor with the laminated-structure interlayer was reduced by one order of magnitude. The reliability enhancement was proved by the Time-Dependent Dielectric Breakdown (TDDB) test, and the optimization results were attributed to the migration inhibition and nonuniform distribution of oxygen vacancies. Without additional materials and a complicated process, the laminated-structure method provides a feasible strategy for improving HZO device reliability.

In vivo spectroscopic characterization of porcine biliary tract tissues: first step in the development of new biliary tract imaging devices.

BACKGROUND: Approximately 400,000 cholecystectomies are performed annually in the United States. The most important complication of the operation is bile duct injury (BDI). Injury prevention relies mostly on an individual surgeon's skill. As of yet no technology has been introduced that will enable surgeons to visualize the bile ducts while operating. Theoretically, such a device could eliminate BDI. Near infrared (NIR) spectroscopy capitalizes on near infrared light's ability to penetrate deeply into tissues and spectroscopic capability to discern tissue's chemical properties. The purpose of this work is to characterize the NIR optical properties of bile containing structures that are needed for later development of a clinically useful probe. METHODS: NIR Spectroscopy combined with visible light spectroscopy was used to determine the spectroscopic properties of the biliary tree and its adjacent structures. Eight anesthetized pigs were used to obtain reflectance measurements using a fiber probe. Radial Basis functions (RBFs) were used to characterize the reflected light spectra. Parameters describing the RBFs were then used to classify tissues based on their observed spectra using machine automation. RESULTS: Biliary tissues, arteries and veins all had unique reflectance spectra. These spectra were characterized by their unique set of RBFs. CONCLUSION: We have developed an optical probe capable of imaging and identifying biliary tract tissues in a porcine model. In this study, we characterized the reflectance properties for bile and blood vessels such that when the probe is applied to the porta hepatis it will enable surgeons to localize important biliary structures prior to any portal dissection, potentially eliminating the risk for inadvertent BDI.