Micro light emitting device and display apparatus including the same
A micro light emitting device includes a first semiconductor layer doped with a first conductivity type, a light emitting layer arranged on an upper surface of the first semiconductor layer, a second semiconductor layer arranged on an upper surface of the light emitting layer and doped with a second conductivity type electrically opposite to the first conductivity type, an insulating layer arranged on an upper surface of the second semiconductor layer, a first electrode arranged on an upper surface of the insulating layer and electrically connected to the first semiconductor layer, a second electrode arranged on the upper surface of the insulating layer and electrically connected to the second semiconductor layer, and an aluminum nitride layer arranged on a lower surface of the first semiconductor layer and having a flat surface.
1 . A micro light emitting device comprising:
a first semiconductor layer doped with a first impurity having a first conductivity;
a light emitting layer arranged on an upper surface of the first semiconductor layer;
a second semiconductor layer arranged on an upper surface of the light emitting layer, the second semiconductor layer being doped with a second impurity having a second conductivity electrically opposite to the first conductivity;
an insulating layer arranged on an upper surface of the second semiconductor layer;
a first electrode arranged on an upper surface of the insulating layer and electrically connected to the first semiconductor layer;
a second electrode arranged on the upper surface of the insulating layer and electrically connected to the second semiconductor layer; and
an aluminum nitride layer arranged on a lower surface of the first semiconductor layer, the aluminum nitride layer comprising a flat surface,
wherein a surface roughness of a surface of the aluminum nitride layer is about 50 nm or less,
wherein a width of the first semiconductor layer is greater than a thickness of the micro light emitting device.
2 . The micro light emitting device of claim 1 , wherein a width of the micro light emitting device is in a range of about 1 μm to about 100 μm.
3 . The micro light emitting device of claim 1 , wherein the thickness of the micro light emitting device is in a range of about 2 μm to about 10 μm, and the width of the first semiconductor layer is in a range of about 5 μm to about 50 μm.
4 . The micro light emitting device of claim 1 , wherein a width of the second semiconductor layer is greater than the thickness of the micro light emitting device.
5 . The micro light emitting device of claim 4 , wherein a side surface of the micro light emitting device is inclined such that the width of the first semiconductor layer is greater than the width of the second semiconductor layer.
6 . The micro light emitting device of claim 1 , wherein the surface roughness of the surface of the aluminum nitride layer is about 10 nm or less.
7 . The micro light emitting device of claim 1 , further comprising an irregular light scattering structure distributed inside the first semiconductor layer.
8 . The micro light emitting device of claim 1 , wherein the aluminum nitride layer comprises a plurality of isolated grooves.
9 . The micro light emitting device of claim 8 , wherein each of the plurality of isolated grooves has a dot shape, and
wherein the plurality of isolated grooves is two-dimensionally arranged in a surface of the aluminum nitride layer.
10 . The micro light emitting device of claim 8 , wherein each the plurality of isolated grooves has a ring shape, and
wherein the plurality of isolated grooves is arranged concentrically in a surface of the aluminum nitride layer.
11 . The micro light emitting device of claim 1 , wherein the second electrode is arranged at a position corresponding to a center of the second semiconductor layer in a horizontal direction, and
wherein the first electrode is arranged at a position corresponding to an edge of the second semiconductor layer in the horizontal direction.
12 . The micro light emitting device of claim 11 , wherein the first electrode has a symmetrical shape surrounding the second electrode.
13 . The micro light emitting device of claim 11 , further comprising a via hole passing through the second semiconductor layer and the light emitting layer,
wherein the insulating layer extends to surround a sidewall of the via hole, and the first electrode is configured to contact the first semiconductor layer through the via hole, and
wherein the second electrode is configured to penetrate the insulating layer and contact the second semiconductor layer.
14 . The micro light emitting device of claim 11 , further comprising a bonding spread prevention wall arranged between the first electrode and the second electrode.
15 . The micro light emitting device of claim 14 , wherein the bonding spread prevention wall has a protruding shape on the upper surface of the insulating layer.
16 . The micro light emitting device of claim 14 , wherein the bonding spread prevention wall has a shape of a groove.
17 . The micro light emitting device of claim 11 , wherein the micro light emitting device has a rectangular cross-section viewed in a vertical direction, and
wherein the first electrode is arranged in two vertex regions facing each other in a diagonal direction.
18 . The micro light emitting device of claim 17 , further comprising a bonding pad arranged in each of two other vertex regions different from the two vertex regions, the two other vertex regions facing each other in another diagonal direction different from the diagonal direction.
19 . A micro light emitting device comprising:
a first electrode on a first surface of the micro light emitting device; and
an aluminum nitride layer on a second surface of the micro light emitting device opposite to the first surface,
wherein a surface roughness of the aluminum nitride layer is 50 nm or less on a surface of the aluminum nitride layer which is opposite to the micro light emitting device,
wherein a first shape of the first electrode is radially symmetrical with respect to a center of the micro light emitting device.
20 . The micro light emitting device of claim 19 , further comprising a second electrode on the first surface,
wherein a second shape of the second electrode is radially symmetrical with respect to the center of the micro light emitting device.
21 . A micro light emitting device comprising:
a first semiconductor layer doped with a first impurity having a first conductivity;
a light emitting layer arranged on an upper surface of the first semiconductor layer;
a second semiconductor layer arranged on an upper surface of the light emitting layer, the second semiconductor layer being doped with a second impurity having a second conductivity electrically opposite to the first conductivity;
an insulating layer arranged on an upper surface of the second semiconductor layer;
a first electrode arranged on an upper surface of the insulating layer and electrically connected to the first semiconductor layer;
a second electrode arranged on the upper surface of the insulating layer and electrically connected to the second semiconductor layer;
a bonding spread prevention wall arranged between the first electrode and the second electrode;
a bonding pad arranged on the upper surface of the insulating layer; and
an aluminum nitride layer arranged on a lower surface of the first semiconductor layer, the aluminum nitride layer comprising a flat surface.