Renu Whig

Spintronics-based devices for Microwave Power Harvesting

Since nearly the beginning, the Schottky diode rules in the development of RF/microwave mixing and rectifying circuits. However, in the specific μW power harvesting applications, the diodes fail to provide satisfying RF-to-DC conversion efficiency mainly due to their high zero-bias junction resistance. This work introduces for the first time a nonlinear component for power rectification based on a recent discovery in spintronics: the spindiode. Along with an analysis of the role of the nonlinearity and the zero bias resistance in the rectification process, it will be shown how the spindiode can provide 10 times more power than a Schottky diode.

Characterization of oxynitride hard mask removal processes for refractory x-ray mask fabrication

Silicon oxynitride removal processes are characterized for incorporation into the refractory x-ray mask fabrication sequence as the hardmask removal step. It is essential that his process not alter final image placement, one of the most critical parameters affecting x-ray mask performance. In this paper, we show that 10:1 buffered HF causes large image placement movement when used on refractory x-ray masks. This is because etching in HF has deleterious effects on TaSi, resulting in highly compressive film stress. Materials analysis indicates the presence of hydrogen in the TaSi films after being exposed to HF, which is most likely affecting the film stress. Alternative processes being investigated include using a more dilute 100:1 buffered HF solution and a CHF3 plasma dry-etch chemistry. Both of these options completely remove the SiON hardmask without causing any significant image placement movement and result in high quality refractory x-ray masks.