Dongyan Zhao

Fabrication of a novel device by release the stress in a reliable way

Processes that define the cantilever sensor from the front side of the wafer are designed to release the stress of the buried oxide layer and top silicon layer. This approach can be applied to enhance the performance of all the cantilever-based sensors. Then, a novel cantilever array sensor was microfabricated for precise bio-marker detection.

Investigation on transient catastrophic optical damage in high power AlGaAs/GaAs laser diodes

The phenomenon of transient catastrophic optical damage (COD) was studied experimentally by means of thermal infrared imaging, photon emission microscope (EMMI), and electron diffraction technology (SAED) under high-resolution transmission electron microscope. We have recorded the dynamics of COD process using thermal infrared camera. The temperature of transient COD has a sudden increase of 32.07 °C when the COD event occurs which maintains less than 8.69 ms accompanying with the sudden decrease of output power. The reverse leakage current was investigated by EMMI. The leakage current of the COD sample increase and the photo in the active region was observed. Moreover, the result obtained from SAED technology identified that the silicon was changed into polycrystalline near the active area, contrasting to the silicon outside active area still remained initial single phase after COD.

Investigation on the ESD failure mechanism of integrated circuits in a 0.11µm CMOS process

The ESD failure mechanism of integrated circuits in a 0.11µm CMOS process was investigated experimentally in detail. The leakage current was presented through I–V measurements, some hotspots were observed on the failed chips when ESD occurring. The study suggested two failure modes in the experiments. One was defined as thermal ESD failure, and the large current between one pad and another pad can be regarded as the key precondition for the occurrence of thermal ESD failure. The other failure mode was electric ESD failure. The defect-current was the main factor for such failure, and occurred mainly in device layer.

Removal of high dose ion-implanted photoresists using dry process

Dry etching process are some of the most familiar MEMS technology. In this paper, we study the rate enhancements observed through operation of the power of plasma source and the oxygen flow rate in a single step at low temperature for high dose implanted photoresist removal.

A new application of SAM in the non-destructive inspection for SIM card

Scanning Acoustic Microscopy (SAM) is a typical inspection method in the semiconductor IC manufacturing industry. Because the die thickness is a key parameter for SIM card, a new method to measure the internal die thickness of SIM card is proposed with SAMs reflective scanning mode. Using this method the internal die thickness of SIM card can be accurately measured without introducing any damages to SIM card. The thickness model and methodology based on the SAM signals have been established. The model was properly verified and calibrated by two real test cases.

Investigation of Electromigration Degradation Mechanism in Ti/Pt/Au Ohmic Contacts to p-GaAs Under High Current Density Stress

The degradation mechanism of Ti/Pt/Au ohmic contacts to p-GaAs was identified experimentally under high direct-current density stress in detail. A revised measuring structure was designed based on the circular transfer length method (CTLM), in which the high current density of

Investigation of thermomechanical stress characteristics in high-power 808-nm AlGaAs/GaAs laser diode bars

0.8\times 10^{5}

Integrated of PDMS microfluidic channel with cantilever based bio-sensor

A/cm2 was applied vertically, while the contact resistance was measured horizontally between two contact electrodes. According to revised CTLM, the specific contact resistance was measured during stress. The results indicated that specific contact resistance showed an exponential dependence on the aging time. The depth profiling results obtained from the Auger electron spectroscopy showed that Pt penetrated into the Au layer during stress. Furthermore, some voids were observed at the Au/Pt interface, and intermixing began to form within metal layer during stress. These results demonstrated that the degradation of Ti/Pt/Au ohmic contacts to p-GaAs was attributed mainly to the electromigration and Joule heating along the current direction under high current density.

Fabrication of a novel cantilever-based device by release the stress in a reliable way

The thermomechanical stress characteristics in high-power 808-nm AlGaAs/GaAs laser diode bars were investigated experimentally and theoretically using infrared thermography and finite element method in detail. The transient thermomechanical stress curves changing with total operation current were measured using infrared thermography. The results indicated that thermomechanical stress of laser diodes chip has a logarithmical dependence on the total operation current. In addition, the dependence of thermomechanical stress on total operation current was analyzed based on finite element method which was great consistent with the experimental results. The calculated results showed that thermomechanical stress of laser diodes chip had a higher increasing rate with higher operation current density, and the plastic deformation would occur when the thermal stress reaches the yield strength.

The mechanical simulation of a special biosensor

A novel cantilever array sensor was micro-fabricated for precise bio-marker detection. The device was fabricated on a SOI wafer with CMOS compatible processes. In order to reducing the effect of k variation due to adsorption, a local biochemical reaction cavity was designed in the free end of the cantilever, the antibody-immobilization was performed in this local area by micro printing technology. This approach can be applied to enhance the performance of all the cantilever-based sensors. The PDMS package is designed to be used for the cantilever sensor which is greatly promoting the practicality of the sensor.