Silicon doped vanadium dioxide (VO2) films were successfully prepared on high purity Si(111) substrate. Confirmed by X-ray diffraction, all samples showed a preference orientation of (011) direction. Introducing silicon led grain sizes decreasing comparing to undoped VO2 film, and this result induced a narrow hysteresis width in MIT performance. Furthermore, silicon doped VO2 films annealing in different temperature presented different phase transition properties. In the electrical, a higher annealing temperature resulted in a decrease of sheet resistance and lowering the transition temperature. In terahertz optical transmittance, silicon doped VO2 films keep an excellent modulation ratio, indicating a great potential in the application of terahertz modulator devices.
A terahertz (THz) microbolometer detector and corresponding real-time imaging system were introduced in this paper. A 10nm NiCr thin film was integrated in the micro-bridge structure as the THz absorption layer by magnetron sputtering and reactive ion etching (RIE), and its improvement of THz absorption was verified by optical characteristics test. Through complicated semiconductor process, a microbolometer detector of 320×240 THz focal plane array (FPA) was prepared. And a real-time imaging system was established to identify the perfomance of this detector. The results demonstrated that the detector could get conscious THz image using a 2.52 THz far-infrared gas laser as THz radiation source.
Patterning of AlCu alloy thin films is a key technology in MEMS fabrication. In this paper, reactive ion etching (RIE)
process of Al-1%Cu films was described using BCl3 and Cl2 as etching gases and N2 and CH4 as neutral gases. A four-step
process was presented to meet the etching requirements using BCl3, Cl2, N2 and CF4 as process gases. Optical emission
spectroscopy (OES) was used to monitor the state of the plasma in real time. The etching endpoint was detected by
detecting the spectral intensity change in the wavelength range of 395 ~ 400nm.
The special technical process was demaned for the reactive ion etching (RIE) of AlCu alloy thin films, such as the
removal of doped Cu, the protection of sidewall and the prevention of chlorine corrosion after etching. In this paper,
Al-1%Cu alloy was etched using BCl3, Cl2 and N2 gases, and CH4 was also added in the etching gases in order to
enhance the sidewall protection. The process was optimized and the multi-step process were abtained. The effect of CH4
on sidewall protection was analyzed. The removal of residue after the etch was also studied.
Silicon nitride (SiNx) thin films were deposited by plasma-enhanced chemical vapor deposition (PECVD) with different
process parameters (frequency, the ratio of SiH4 to NH3 gas, and the gas composition), and reactive ion etching (RIE)
experiments of these SiNx thin films were carried out in order to research the relationship between PECVD process
parameters and the etching rate (ER). The SiNx film properties (density, film composition and refractive index), which
affected the etching rate, were also studed.