In the last years, silicon micromachining techniques based on high aspect ratio reactive ion etching with gas chopping have been developed. There the gas flow of etching and deposition gas precursors is chopped which results in controllable sidewall passivation and high anisotropy. However, the rippled sidewalls are a serious limit for various applications. We report on the development of a novel gas chopping etching technique (GCET) process in order to achieve a smooth (rippled free) sidewall surface. As the direct etch mask, we used a 1 or 2-μm-thick resist layer, which was lithographically patterned. The novelty of the process consists in the replacing of the isotropic etching step by an anisotropic etching step. In this way we omit the main source for sidewall ripples. GCET combined with inductively coupled plasmas and fluorine chemistry provide very high etch rates and good control of the sidewall slope. These techniques also can be applied to conventional reactive ion etching equipment with Cl or F based plasma chemistry. However, the techniques used in this study have lower selectivity (in range of 30) than the conventional GCET. A SiON/Si selectivity as high as 50 has been achieved.
The movement of a micro cantilever was detected via a self constructed portable data acquisition prototype system which integrates a linear array of 32 1D amorphous silicon position sensitive detectors (PSD). The system was mounted on a microscope using a metal structure platform and the movement of the 30 μm wide by 400 μm long cantilever was tracked by analyzing the signals acquired by the 32 sensor array electronic readout system and the relevant data algorithm. The obtained results show a linear behavior of the photocurrent relating X and Y movement, with a non-linearity of about 3%, a spatial resolution of less than 2 μm along the lateral dimension of the sensor as well as of less than 3 μm along the perpendicular dimension of the sensor, when detecting just the micro-cantilever, and a spatial resolution of less than 1 μm when detecting the holding structure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.