Browsing by Author "Hsiao, Shih-Kuang"

Now showing 1 - 3 of 3

460-nm InGaN-Based LEDs Grown on Fully Inclined Hemisphere-Shape-Patterned Sapphire Substrate With Submicrometer Spacing
(2009-10-01)
Chang, Chia-Ta
;
Hsiao, Shih-Kuang
;
Chang, Edward Yi
;
Hsiao, Yu-Lin
;
Huang, Jui-Chien
This letter investigates 460-nm InGaN-based light-emitting diodes (LEDs) grown on a hemisphere-shape-patterned sapphire substrate (HPSS) with submicrometer spacing. The full-width at half-maximum of the (102) plane rocking curves for GaN layer grown on a conventional sapphire substrate (CSS) and HPSS are 480 and 262 arcsec, respectively. Such improvement is due to the reduction of the pure edge threading dislocations. At the forward current of 20 mA, the light output power of the LEDs grown on CSS and HPSS were 4.05 and 5.86 mW, respectively. This improvement of 44% light-output power can be attributed to the improved quality of the material and the increase of the light extraction by the fully inclined facets of the HPSS.
Changes of Electrical Characteristics for AlGaN/GaN HEMTs Under Uniaxial Tensile Strain
(2009-03-01)
Chang, Chia-Ta
;
Hsiao, Shih-Kuang
;
Chang, Edward Yi
;
Lu, Chung-Yu
;
Huang, Jui-Chien
This letter investigates the characteristics of unpassivated AlGaN/GaN high-electron mobility transistors (HEMTs) under uniaxial tensile strain. Mechanical stress can produce additional charges that change the HEMT channel current. is phenomenon is dependent upon gate orientation and may be the result of the piezoelectric effect and changes in electron mobility due to the applied uniaxial stress. In addition, results show that tensile strain reduces the transient current, which is, likely due to the additional donorlike surface states created through the piezoelectric effect.
Method for forming required pattern on semiconductor substrate by thermal reflow technique
(2010-06-24)
Chang, Yi Edward
;
Chang, Chia-Ta
;
Hsiao, Shih-Kuang
The invention is disclosed that pattern on semiconductor substrate is fabricated by thermal reflow technique. Also, the pattern on semiconductor substrate having different sub-micron spacings can be fabricated by using different time for the thermal reflow technique process.