摘要:
Low profile, side-emitting LEDs are described that generate white light, where all light is emitted within a relatively narrow angle generally parallel to the surface of the light-generating active layer. The LEDs enable the creation of very thin backlights for backlighting an LCD. In one embodiment, the LED emits blue light and is a flip chip with the n and p electrodes on the same side of the LED. Separately from the LED, a transparent wafer has deposited on it a red and green phosphor layer. The phosphor color temperature emission is tested, and the color temperatures vs. positions along the wafer are mapped. A reflector is formed over the transparent wafer. The transparent wafer is singulated, and the phosphor/window dice are matched with the blue LEDs to achieve a target white light color temperature. The phosphor/window is then affixed to the LED.
摘要:
A light emitting device includes a semiconductor structure comprising a light emitting layer disposed between an n-type region and a p-type region, a metal p-contact disposed on the p-type region, and a metal n-contact disposed on the n-type region. The metal p-contact and the metal n-contact are both formed on the same side of the semiconductor structure. The light emitting device is connected to a mount by a bonding structure. The bonding structure includes a plurality of metal regions separated by gaps and a metal structure disposed between the light emitting device and the mount proximate to an edge of the light emitting device. The metal structure is configured such that during bonding, the metal structure forms a continuous seal between the light emitting device and the mount.
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 compliant bonding structure is disposed between a semiconductor light emitting device and a mount. When the semiconductor light emitting device is attached to the mount, for example by providing pressure, heat, and/or ultrasonic energy to the semiconductor light emitting device, the compliant bonding structure collapses to partially fill a space between the semiconductor light emitting device and the mount. In some embodiments, the compliant bonding structure is plurality of metal bumps that undergo plastic deformation during bonding. In some embodiments, the compliant bonding structure is a porous metal layer.
摘要:
A semiconductor structure comprises a light emitting layer disposed between an n-type region and a p-type region. A wavelength converting material is disposed over the semiconductor structure. The wavelength converting material is configured to absorb light emitted by the semiconductor structure and emit light of a different wavelength. A filter configured to reflect blue ambient light is disposed over the wavelength converting material. A scattering structure is disposed over the wavelength converting layer. The scattering structure is configured to scatter light. In some embodiments, the scattering structure is a transparent material having a rough surface, containing non-wavelength-converting particles that appear substantially white in ambient light, or including both a rough surface and white particles.
摘要:
A compliant bonding structure is disposed between a semiconductor light emitting device and a mount. When the semiconductor light emitting device is attached to the mount, for example by providing pressure, heat, and/or ultrasonic energy to the semiconductor light emitting device, the compliant bonding structure collapses to partially fill a space between the semiconductor light emitting device and the mount. In some embodiments, the compliant bonding structure is plurality of metal bumps that undergo plastic deformation during bonding. In some embodiments, the compliant bonding structure is a porous metal layer.
摘要:
Methods of fabricating relaxed layers of semiconductor materials include forming structures of a semiconductor material overlying a layer of a compliant material, and subsequently altering a viscosity of the compliant material to reduce strain within the semiconductor material. The compliant material may be reflowed during deposition of a second layer of semiconductor material. The compliant material may be selected so that, as the second layer of semiconductor material is deposited, a viscosity of the compliant material is altered imparting relaxation of the structures. In some embodiments, the layer of semiconductor material may comprise a III-V type semiconductor material, such as, for example, indium gallium nitride. Methods of fabricating semiconductor structures and devices are also disclosed. Novel intermediate structures are formed during such methods. Engineered substrates include a plurality of structures comprising a semiconductor material disposed on a layer of material exhibiting a changeable viscosity.
摘要:
The present invention provides methods for forming at least partially relaxed strained material layers on a target substrate. The methods include forming islands of the strained material layer on an intermediate substrate, at least partially relaxing the strained material islands by a first heat treatment, and transferring the at least partially relaxed strained material islands to the target substrate. The at least partial relaxation is facilitated by the presence of low-viscosity or compliant layers adjacent to the strained material layer. The invention also provides semiconductor structures having an at least partially relaxed strained material layer, and semiconductor devices fabricated using an at least partially relaxed strained material layer.
摘要:
In one embodiment, an AlInGaP LED includes a bottom n-type layer, an active layer, a top p-type layer, and a thick n-type GaP layer over the top p-type layer. The thick n-type GaP layer is then subjected to an electrochemical etch process that causes the n-type GaP layer to become porous and light-diffusing. Electrical contact is made to the p-GaP layer under the porous n-GaP layer by providing metal-filled vias through the porous layer, or electrical contact is made through non-porous regions of the GaP layer between porous regions. The LED chip may be mounted on a submount with the porous n-GaP layer facing the submount surface. The pores and metal layer reflect and diffuse the light, which greatly increases the light output of the LED. Other embodiments of the LED structure are described.
摘要:
A semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region is attached to a compound substrate including a host which provides mechanical support to the device and a ceramic layer including a luminescent material. In some embodiments the compound substrate includes a crystalline seed layer on which the semiconductor structure is grown. The ceramic layer is disposed between the seed layer and the host. In some embodiments, the compound substrate is attached to the semiconductor structure after growth of the structure on a conventional growth substrate. In some embodiments, the compound substrate is spaced apart from the semiconductor structure and does not provide mechanical support to the structure. In some embodiments, the ceramic layer has a thickness less than 500 μm.