In this paper, we report the results of our investigation about 940nm AlGaAs/InGaAs single mode laser diodes adopting graded index separate confinement hetero structures (GRIN-SCH) and p, n-clad asymmetric structures with improved temperature and small divergence beams characteristics under the high output power operation for a 3D motion recognition sensors. The GRIN-SCH design provides good carrier confinement and prevents current leakage by adding a grading layer between clad and waveguide layers. In addition, the dopant concentration of the cladding layer is optimized to reduce resistance and internal loss. At the optical power 300mW, measured average values of threshold current (Ith), operating current (Iop), slop efficiency (SE), operating voltage (Vop), peak wavelength (λ) are 80mA, 352mA, 1.12mW/mA, 1.87V, 940nm respectively. Also, we could obtain catastrophic optical damage (COD) of 750mW and excellent long-term reliability characteristic 60°C with TO-56 package. From the experimental measurement results, the developed 940nm high power laser diode is suitable optical source for the sensor applications including 3D motion recognition sensors.
The satellite-derived atmospheric motions vectors (AMVs) are useful for weather analysis such as tropical low, wind
shear, and jet location and data assimilation into numerical weather prediction model. The AMV's accuracy is sensitive
to the various components like target selection approaches, height assignment (HA) methods and so on, which should be
optimized and improved. AMVs are retrieved by identifying and tracking targets dynamically through the use of
advanced pattern-matching techniques based on cross-correlation statistics. In tracking targets, the optimal target box
size, grid size, satellite image time interval and target location decision method should be determined for detecting cloud
structure. The pixel selection method for the representative cloudy radiance on HA is also investigated. The current
operational algorithm uses 15% coldest pixel temperature for infrared and water vapor channels and the method would
be modified through sensitivity tests for each channel. In addition, the correction method for cloud base height and its
effects are validated.
With the shrunken device rule below 130nm, the patterning of smaller contact hole with enough process margin is required for mass production. Therefore, shrinking technology using thermal reflow process has been applied for smaller contact hole formation. In this paper, we have investigated the effects of chemical characteristics such as molecular weight, blocking ratio of resin, cross-linker amount and solvent type with its composition to reflow process of resist and found the optimized chemical composition for reflow process applicable condition. And several process conditions like resist coating thickness and multi-step thermal reflow method have been also evaluated to stabilize the pattern profile and improve CD uniformity after reflow process. From the experiment results, it was confirmed that the effect of crosslinker in resist to reflow properties such as reflow temperature and reflow rate were very critical and it controlled the pattern profile during reflow processing. And also, it showed stable CD uniformity and improved resist properties for top loss, film shrinkage and etch selectivity. The application of lower coating thickness of resist induced symmetric pattern profile even at edge with wider process margin. The introduction of two-step baking method for reflow process showed uniform CD value, also. It is believed that the application of resist containing crosslinker and optimized process conditions for smaller contact hole patterning is necessary for the mass production with a design rule below 130nm.