37results about How to "Improved current spread" patented technology

A new transparent conducting oxide (TCO), which can be expressed as Al_xGa_3−x−yIn_5+ySn_2−zO_16−2z; 0≦x<1, 0<y<3, 0≦z<2, has been used to improve the brightness and current spreading in GaN base LED process. The optical properties of this system are superior to regular Ni/Au transparent conducting layer in blue-green region, and the new Al₂O₃—Ga₂O₃—In₂O₃—SnO₂ system is able to increase the brightness at 1.5˜2.5 time to compare to regular process. Furthermore, the new transparent conducting oxide thin film has the highest conductivity, which is better than the Ni/Au transparent conducting thin film.

The invention discloses a micro-scale flip LED (Light Emitting Diode) chip and a manufacturing method thereof. A GaN epitaxial layer for manufacturing the LED is of a table structure, both the table base and the table surface of the table structure are in a round table shape, n- electrode rings are distributed on the table base, current spreading rings are distributed at the edge of the top of the table surface, the current spreading material does not diffuse ions at the temperature of 300 DEG C, a passivation layer is arranged on the edge of the top of the current spreading rings and the side wall of the table structure, a dielectric insulating layer and a distributed Bragg reflector layer having the periodic number not smaller than 1 are formed on the passivation layer by adopting chemical vapor deposition, and a p- reflecting electrode layer covers the top of the table surface and the side wall of the passivation layer. The method can improve the reflectivity of a reflector, simultaneously avoids the phenomenon of electric leakage caused by metal diffusion in the reflecting electrode layer, and has relatively large alignment tolerance in the photolithography technique.

The invention discloses a III-group nitride light-emitting diode (LED) and a manufacturing method thereof. The LED comprises a substrate and a semiconductor epitaxial laminate which is laminated on the substrate, wherein the semiconductor epitaxial laminate sequentially comprises an N type layer, a luminescent layer and a P type layer from top to bottom. The LED is characterized in that: an N type layer table face is formed in the N type layer by etching a part of the semiconductor epitaxial laminate; an N type electrode is arranged on the N type layer table face; a P type electrode is arranged on the upper surface of the un-etched part of the P type layer; the N type layer also comprises a uniformly doped layer of which the doping concentration is consistent and a modulation doped layer of which the doping concentration is changeable; and the modulation doped layer is arranged between the uniformly doped layer and the luminescent layer. A doped mode of the modulation doped layer is gradual transition doping which connects uniformly doped layer and the luminescent layer of which the doping concentration is consistent. The concentration change trend is decrease progressively change from the uniformly doped layer to the luminescent layer. By the LED and the manufacturing method, the crystal quality and the luminance uniformity can be obviously improved, and the lighting effect is improved.

The invention relates to a copper substrate-based nitride LED vertical chip and a preparation method thereof. The copper substrate-based nitride LED vertical chip comprises an n-type electrode, a two-dimensional derived film, a nitride epitaxial layer and a p-type electrode, wherein the two-dimensional derived film is attached onto the n-type electrode; the nitride epitaxial layer is attached onto the two-dimensional derived film; the p-type electrode is attached onto the nitride epitaxial layer. The preparation method for the copper substrate-based nitride LED vertical chip comprises the following steps: after a copper substrate-based nitride LED epitaxial wafer is prepared, piercing a hole from the back surface of a copper substrate to a buffer layer or an n-type electron injection layer by using a hole piercing process; manufacturing a metal channel structure for realizing the contact with the n-type electron injection layer, and simultaneously realizing the conduction between the n-type electron injection layer and the copper substrate; manufacturing the p-type electrode on the top of a p-type cavity injection layer. The nitride LED vertical chip disclosed by the invention has the characteristics of better current expanding, lower thermal resistance, higher reliability and the like, and is very suitable for the application directions of high current density driving and high optical power density output.

The invention discloses an electrode preparation method for improving the current expansion and luminous efficiency of a GaAs-based light-emitting diode, and the method comprises the steps: preparing a patterned recessed region on a GaAs-based epitaxial wafer through photoresist coating and plasma etching, and removing photoresist; depositing an ITO film on the GaAs-based epitaxial wafer, and carrying out the thermal annealing of the ITO film; carrying out sequential vapor plating of a plurality of metal film layers on the ITO film through photoresist coating and electron-beam evaporation, and forming a pattern electrode, wherein the pattern electrode comprises a pasting layer, a reflection layer, a blocking layer, and a welding layer; removing the metal films in a region outside the pattern electrode through employing a peeling method, and completing the preparation of a P electrode of the GaAs-based light-emitting diode; removing the residual photoresist; thinning a GaAs-based substrate of the GaAs-based epitaxial wafer, carrying out the vapor plating of one metal film layer on the surface of the GaAs-based substrate, and completing the preparation of the N electrode of the GaAs-based light-emitting diode. The method improves the current expansion of the GaAs-based light-emitting diode through employing the ITO film.

The invention discloses a laser diode based on a gallium nitride single crystal substrate and a preparation method of the laser diode. The laser diode comprises the GaN single-crystal substrate, an n-type GaN layer, an n-type limiting layer, a lower waveguide layer, a composite quantum well active region, an electron blocking layer, an upper waveguide layer, a p-type limiting layer and a p-type GaN layer which are sequentially stacked from bottom to top. According to the invention, the high-quantum efficiency stress regulation and control active region structure, the novel optical waveguide layer structure and the novel limiting layer structure of the gallium nitride-based laser diode are designed and optimized; the laser diode is prepared on the low-dislocation-density GaN single-crystalsubstrate; the technical difficulty of epitaxial preparation of a GaN-based laser is eliminated; and a GaN-based laser with high reliability and high quantum efficiency can be obtained.

The invention relates to a light emitting diode using ITO regional sheet resistance change to improve current spreading and a manufacturing method. The light emitting diode comprises an epitaxial wafer grown on a substrate, an ITO film located on the epitaxial wafer, a metal electrode and a passivation layer; three ITO regions with different sheet resistances are located on the ITO film, a high-sheet resistance ITO region III is located below the metal electrode, a low-sheet resistance ITO region I is formed through a mask pattern, and the low-sheet resistance ITO region I extends to the edge through using the metal electrode as the center and has a branch shape. According to the light emitting diode using the ITO regional sheet resistance change to improve the current spreading and the manufacturing method, through improving or lowering the sheet resistance on the selective region of the ITO layer, the current spreading route guidance is realized, without increasing a current blocking layer, the current spreading uniformity of the light emitting diode can be improved through the regional treatment of the current spreading layer ITO, the light emitting efficiency is improved, and the high voltage of the chip is avoided.

The invention discloses a light emitting diode epitaxial wafer and a preparation method thereof, and belongs to the technical field of semiconductors. The light-emitting diode epitaxial wafer comprises a substrate, an N-type semiconductor layer, a stress release layer, an active layer and a P-type semiconductor layer, wherein the N-type semiconductor layer, the stress release layer, the active layer and the P-type semiconductor layer are sequentially stacked on the substrate; the stress release layer comprises a plurality of composite structures which are stacked in sequence, wherein each composite structure comprises a first sub-layer, a second sub-layer, a third sub-layer and a fourth sub-layer which are stacked in sequence; the first sub-layer is made of non-doped indium gallium nitride, the second sub-layer is made of non-doped aluminum nitride, the third sub-layer is made of silicon nitride, and the fourth sub-layer is made of non-doped gallium nitride. According to the light-emitting diode epitaxial wafer, the photoelectric property of the LED is finally improved.

The invention discloses a vertical high voltage light emitting diode chip and a manufacturing method thereof. With the design of the vertical high voltage light emitting diode chip, the back surface electrode in a first chip region is electrically connected with a conductive substrate through a hole and a bonding layer and the back surface electrode is exposed without etching in the first chip region, thereby ensuring that the effective light emitting area of the vertical high voltage light emitting diode chip is large; besides, the back surface electrode of the first chip region does not needto be wired, thereby saving cost and improving reliability; in addition, the current spreading of each chip region is vertical, and the back surface electrode of the first chip region and the front surface electrode of the Nth chip region form a vertical structure so that the current spreading of the vertical high voltage light emitting diode chip is good, and the current resistance ability can be improved by avoiding current congestion; furthermore, the vertical high voltage light emitting diode chip has a better light type and meets the Lambert distribution and is easier to distribute light.

The invention discloses a GaN-based vertical structure micro-cavity Micro-LED based on an electroplating technology and a preparation method thereof. The micro-cavity Micro-LED is narrow in light-emitting full width at half maximum and good in light-emitting directivity; thickness of a chip is reduced, and a metal reflector of the p-GaN layer (5) and a dielectric film reflector of the n-GaN layerare used as end faces of a resonant cavity to form a resonant micro-cavity structure in the vertical direction, so side wall light emission is inhibited, front light emission directivity is improved,and the crosstalk effect between adjacent pixels of Micro-LED display is reduced. Meanwhile, the resonant micro-cavity structure selects a specific wavelength, so the light-emitting spectrum is narrowed, the spectral purity is higher, the display threshold of the Micro-LED is improved, a Micro-LED active region of the vertical structure is large in area, and n-GaN light absorption is less, the current expansion is good, the voltage is low, the current density is small, and advantages in the aspects of lighting effect, saturation current and long-term reliability are achieved; and secondly, a Cu substrate has good electrical conductivity and thermal conductivity, and thermal resistance of the chip is small.