DIRECT-BONDED OPTOELECTRONIC DEVICES
Direct-bonded LED arrays and applications are provided. An example process fabricates a LED structure that includes coplanar electrical contacts for p-type and n-type semiconductors of the LED structure on a flat bonding interface surface of the LED structure. The coplanar electrical contacts of the flat bonding interface surface are direct-bonded to electrical contacts of a driver circuit for the LED structure. In a wafer-level process, micro-LED structures are fabricated on a first wafer, including coplanar electrical contacts for p-type and n-type semiconductors of the LED structures on the flat bonding interface surfaces of the wafer. At least the coplanar electrical contacts of the flat bonding interface are direct-bonded to electrical contacts of CMOS driver circuits on a second wafer. The process provides a transparent and flexible micro-LED array display, with each micro-LED structure having an illumination area approximately the size of a pixel or a smallest controllable element of an image represented on a high-resolution video display.
1 . A bonded device, comprising:
a first element comprising a plurality of optoelectronic devices, the first element having an upper surface and a lower surface opposite the upper surface; and
a second element comprising a plurality of transistors, the second element having an upper surface and a lower surface opposite the upper surface, the second element comprising dielectric-refilled non-transistor portions between semiconductor transistor portions;
the lower surface of the first element being directly bonded to the upper surface of the second element at a bond interface; and
a plurality of electrical connections electrically connecting the optoelectronic devices of the first element to the plurality of transistors of the second element through the bond interface.
2 . The bonded device of claim 1 , wherein the plurality of electrical connections includes electrodes extending from the lower surface of the second element through the dielectric-refilled non-transistor portions to the optoelectronic devices.
3 . The bonded device of claim 1 , wherein the lower surface of the first element and the upper surface of the second element comprise directly bonded dielectric surfaces.
4 . The bonded device of claim 1 , wherein the electrical connections include electrodes through the dielectric-refilled non-transistor portions.
5 . The bonded device of claim 1 , wherein the dielectric-refilled non-transistor portions separate the semiconductor transistor portions.
6 . A bonded device, comprising:
a first element comprising at least one optoelectronic device, the first element having an upper surface and a lower surface opposite the upper surface; and
a second element comprising a semiconductor active device portion, the second element having an upper surface and a lower surface opposite the upper surface, the second element comprising dielectric-refilled non-active portions adjacent the semiconductor active device portion;
the lower surface of the first element being directly bonded to the upper surface of the second element at a bond interface; and
a plurality of electrical connections electrically connecting the optoelectronic devices of the first element to the semiconductor active device portions of the second element through the bond interface.
7 . The bonded device of claim 6 , wherein the plurality of electrical connections includes electrodes extending from the lower surface of the second element through the dielectric-refilled non-active portions to the optoelectronic devices.
8 . The bonded device of claim 6 , wherein the at least one optoelectronic device comprises a light emitting diode.
9 . A bonded device, comprising:
an optoelectronic layer comprising an array of optoelectronic devices, including a first optoelectronic device;
an active device layer directly bonded to the optoelectronic layer, the active device layer comprising a first active device region, and a first non-active device region, wherein the first non-active device region is a dielectric-refilled region; and
a plurality of electrical connections to electrically connect at least the first optoelectronic device to the first active device region.
10 . The bonded device of claim 9 , wherein the first optoelectronic device comprises a light emitting diode.
11 . The bonded device of claim 9 , further comprising a bonding interface between the optoelectronic layer and the active device layer, wherein the optoelectronic layer outputs light away from the bonding interface.
12 . The bonded device of claim 11 , wherein the optoelectronic layer comprises an optically transparent surface opposite the bonding interface, and wherein the light propagates through the optically transparent surface.
13 . The bonded device of claim 9 , wherein the active device layer comprises a driver circuit.
14 . The bonded device of claim 9 , further comprising a cooling structure to dissipate heat generated by the bonded device.
15 . The bonded device of claim 9 , wherein the active device layer comprises an upper surface adjacent to the optoelectronic layer and a bottom surface opposite the upper surface, and wherein one or more additional layers are disposed over the bottom surface of the active device layer.
16 . The bonded device of claim 15 , wherein the one or more additional layers comprise build-up layers.
17 . The bonded device of claim 16 , wherein the one or more additional layers electrically connect to at least one of a memory, a printed circuit board, or a sensor.
18 . The bonded device of claim 15 , wherein one or both of a lower surface of the optoelectronic layer or the upper surface of the active device layer is a plasma-activated surface.
19 . The bonded device of claim 9 , further comprising a plurality of optical elements integrated over the optoelectronic layer.
20 . The bonded device of claim 19 , wherein the plurality of optical elements comprises at least one of a beam steering element or a beam shaping element.