摘要:
LED epitaxial layers (n-type, p-type, and active layers) are grown on a substrate. For each die, the n and p layers are electrically bonded to a package substrate that extends beyond the boundaries of the LED die such that the LED layers are between the package substrate and the growth substrate. The package substrate provides electrical contacts and conductors leading to solderable package connections. The growth substrate is then removed. Because the delicate LED layers were bonded to the package substrate while attached to the growth substrate, no intermediate support substrate for the LED layers is needed. The relatively thick LED epitaxial layer that was adjacent the removed growth substrate is then thinned and its top surface processed to incorporate light extraction features. There is very little absorption of light by the thinned epitaxial layer, there is high thermal conductivity to the package because the LED layers are directly bonded to the package substrate without any support substrate therebetween, and there is little electrical resistance between the package and the LED layers so efficiency (light output vs. power input) is high. The light extraction features of the LED layer further improves efficiency.
摘要:
LED epitaxial layers (n-type, p-type, and active layers) are grown on a substrate. For each die, the n and p layers are electrically bonded to a package substrate that extends beyond the boundaries of the LED die such that the LED layers are between the package substrate and the growth substrate. The package substrate provides electrical contacts and conductors leading to solderable package connections. The growth substrate is then removed. Because the delicate LED layers were bonded to the package substrate while attached to the growth substrate, no intermediate support substrate for the LED layers is needed. The relatively thick LED epitaxial layer that was adjacent the removed growth substrate is then thinned and its top surface processed to incorporate light extraction features. There is very little absorption of light by the thinned epitaxial layer, there is high thermal conductivity to the package because the LED layers are directly bonded to the package substrate without any support substrate therebetween, and there is little electrical resistance between the package and the LED layers so efficiency (light output vs. power input) is high. The light extraction features of the LED layer further improves efficiency.
摘要:
LED epitaxial layers (n-type, p-type, and active layers) are grown on a substrate. For each die, the n and p layers are electrically bonded to a package substrate that extends beyond the boundaries of the LED die such that the LED layers are between the package substrate and the growth substrate. The package substrate provides electrical contacts and conductors leading to solderable package connections. The growth substrate is then removed. Because the delicate LED layers were bonded to the package substrate while attached to the growth substrate, no intermediate support substrate for the LED layers is needed. The relatively thick LED epitaxial layer that was adjacent the removed growth substrate is then thinned and its top surface processed to incorporate light extraction features. There is very little absorption of light by the thinned epitaxial layer, there is high thermal conductivity to the package because the LED layers are directly bonded to the package substrate without any support substrate therebetween, and there is little electrical resistance between the package and the LED layers so efficiency (light output vs. power input) is high. The light extraction features of the LED layer further improves efficiency.
摘要:
A substrate including a host and a seed layer bonded to the host is provided, then a semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region is grown on the seed layer. In some embodiments, a bonding layer bonds the host to the seed layer. The seed layer may be thinner than a critical thickness for relaxation of strain in the semiconductor structure, such that strain in the semiconductor structure is relieved by dislocations formed in the seed layer, or by gliding between the seed layer and the bonding layer an interface between the two layers. In some embodiments, the host may be separated from the semiconductor structure and seed layer by etching away the bonding layer.
摘要:
Described is a process for forming an LED structure using a laser lift-off process to remove the growth substrate (e.g., sapphire) after the LED die is bonded to a submount. The underside of the LED die has formed on it anode and cathode electrodes that are substantially in the same plane, where the electrodes cover at least 85% of the back surface of the LED structure. The submount has a corresponding layout of anode and cathode electrodes substantially in the same plane. The LED die electrodes and submount electrodes are ultrasonically welded together such that virtually the entire surface of the LED die is supported by the electrodes and submount. Other bonding techniques may also be used. No underfill is used. The growth substrate, forming the top of the LED structure, is then removed from the LED layers using a laser lift-off process. The extremely high pressures created during the laser lift-off process do not damage the LED layers due to the large area support of the LED layers by the electrodes and submount.
摘要:
A coaching device and method for providing emergency medical care instructions is shown. The device can include a memory, an audio input, an audio output, a visual display, and a processor. The memory stores a file set made up of multiple question files. The question files include audio data representing a spoken question, at least one valid answer proposed for the question, and visual material. The visual material can be a text version of the question or a valid answer or a visual illustration of the subject matter of the question. Each question file is linked with at least one other question file. A program manages the question files by playing a question, detecting a spoken valid answer to the spoken question, and loading another question file linked to the detected answer. The modular set of interrelated questions provides the rescuer with highly interactive instructions.
摘要:
A semiconductor light emitting device includes an in-plane active region that emits linearly-polarized light. An in-plane active region may include, for example, a {11{overscore (2)}0} or {10{overscore (1)}0} InGaN light emitting layer. In some embodiments, a polarizer oriented to pass light of a polarization of a majority of light emitted by the active region serves as a contact. In some embodiments, two active regions emitting the same or different colored light are separated by a polarizer oriented to pass light of a polarization of a majority of light emitted by the bottom active region, and to reflect light of a polarization of a majority of light emitted by the top active region. In some embodiments, a polarizer reflects light scattered by a wavelength converting layer.
摘要:
A semiconductor structure includes an n-type region, a p-type region, and a III-nitride light emitting layer disposed between the n-type region and the p-type region. The III-nitride light emitting layer has a lattice constant greater than 3.19 Å. Such a semiconductor structure may be grown on a substrate including a host and a seed layer bonded to the host. In some embodiments, a bonding layer bonds the host to the seed layer. The seed layer may be thinner than a critical thickness for relaxation of strain in the semiconductor structure, such that strain in the semiconductor structure is relieved by dislocations formed in the seed layer, or by gliding between the seed layer and the bonding layer an interface between the two layers. In some embodiments, the host may be separated from the semiconductor structure and seed layer by etching away the bonding layer.
摘要:
A device structure includes a III-nitride wurtzite semiconductor light emitting region disposed between a p-type region and an n-type region. A bonded interface is disposed between two surfaces, one of the surfaces being a surface of the device structure. The bonded interface facilitates an orientation of the wurtzite c-axis in the light emitting region that confines carriers in the light emitting region, potentially increasing efficiency at high current density.
摘要:
A semiconductor light emitting device includes an n-type region, a p-type region, and light emitting region disposed between the n- and p-type regions. The n-type, p-type, and light emitting regions form a cavity having a top surface and a bottom surface. Both the top surface and the bottom surface of the cavity may have a rough surface. For example, the surface may have a plurality of peaks separated by a plurality of valleys. In some embodiments, the thickness of the cavity is kept constant by incorporating an etch-stop layer into the device, then thinning the layers of the device by a process that terminates on the etch-stop layer.