A semiconductor device comprises a substrate, one or more first III-semiconductor layers, and a plurality of superlattice structures between the substrate and the one or more first layers. The plurality of superlattice structures comprises an initial superlattice structure and one or more further superlattice structures between the initial superlattice structure and the one or more first layers. The plurality of superlattice structures is configured such that a strain-thickness product of semiconductor layer pairs in each superlattice structure of the one or more further superlattice structures is greater than or equal to a strain-thickness product of semiconductor layer pairs in superlattice structure(s) of the plurality of superlattice structures between that superlattice structure and the substrate. The plurality of superlattice structures is also configured such that a strain-thickness product of semiconductor layer pairs in at least one of the one or more further superlattice structures is greater than a strain-thickness product of semiconductor layer pairs in the initial superlattice structure.

An epitaxial structure and a manufacturing method thereof, and a light-emitting diode (LED) device are provided. The epitaxial structure includes an N-type semiconductor layer, a multiple quantum well (MQW) active layer, and a P-type semiconductor layer sequentially stacked in a growth direction. The MQW active layer includes a front MQW active layer and a back MQW active layer sequentially stacked in the growth direction. The front MQW active layer includes at least two groups of first quantum barrier layers and first quantum well layers alternately stacked. The back MQW active layer includes at least two groups of second quantum barrier layers and second quantum well layers alternately stacked. A content of an aluminum (Al) component in each second quantum well layer is gradually increased in the growth direction, and a content of a gallium (Ga) component in each second quantum well layer is gradually decreased in the growth direction.

A semiconductor thin film structure may include a substrate, a buffer layer on the substrate, and a semiconductor layer on the buffer layer, such that the buffer layer is between the semiconductor layer and the substrate. The buffer layer may include a plurality of unit layers. Each unit layer of the plurality of unit layers may include a first layer having first bandgap energy and a first thickness, a second layer having second bandgap energy and a second thickness, and a third layer having third bandgap energy and a third thickness. One layer having a lowest bandgap energy of the first, second, and third layers of the unit layer may be between another two layers of the first, second, and third layers of the unit layer.

A method for making a device. The method comprises forming a buffer layer on a substrate; forming a periodically doped layer on the buffer layer; forming one or more wires on the periodically doped layer, the wires being chosen from nanowires and microwires; and introducing porosity into the periodically doped layer to form a porous distributed Bragg reflector (DBR). Various devices that can be made by the method are also disclosed.

A semiconductor structure (100) comprising: a substrate (102), a first layer (106) of Al.sub.XGa.sub.YIn.sub.(1−X−Y)N disposed on the substrate, stacks (107, 109) of several second and third layers (108, 110) alternating against each other, between the substrate and the first layer, a fourth layer (112) of Al.sub.XGa.sub.YIn.sub.(1−X−Y)N, between the stacks, a relaxation layer of AlN disposed between the fourth layer and one of the stacks, and, in each of the stacks: the level of Ga of the second layers increases from one layer to the next in a direction from the substrate to the first layer, the level of Ga of the third layers is constant or decreasing from one layer to the next in said direction, the average mesh parameter of each group of adjacent second and third layers increasing from one group to the next in said direction, the thickness of the second and third layers is less than 5 nm.

A GaN-on-Si device structure and a method of fabrication are disclosed for improved die yield and device reliability of high current/high voltage lateral GaN transistors. A plurality of conventional GaN device structures comprising GaN epi-layers are fabricated on a silicon substrate (GaN-on-Si die). After processing of on-chip interconnect layers, a trench structure is defined around each die, through the GaN epi-layers and into the silicon substrate. A trench cladding is provided on proximal sidewalls, comprising at least one of a passivation layer and a conductive metal layer. The trench cladding extends over exposed surfaces of the GaN epi-layers, over the interface region with the substrate, and over the exposed surfaces of the interconnect layers. This structure reduces risk of propagation of dicing damage and defects or cracks in the GaN epi-layers into active device regions. A metal trench cladding acts as a barrier for electro-migration of mobile ions.

A silicon carbide crystal includes a seed layer, a bulk layer, and a stress buffering structure formed between the seed layer and the bulk layer. The seed layer, the bulk layer, and the stress buffering structure are each formed with a dopant that cycles between high and low dopant concentration. The stress buffering structure includes a plurality of stacked buffer layers and a transition layer over the buffer layers. The buffer layer closest to the seed layer has the same variation trend of the dopant concentration as the buffer layer closest to the transition layer, and the dopant concentration of the transition layer is equal to the dopant concentration of the seed layer.

Embodiments of present invention provide a semiconductor structure. The semiconductor structure includes a plurality of sections from a top to a bottom thereof, wherein the plurality of sections has a same chemical composition and at least two different strains. For example, in one embodiment, the plurality of sections has a same chemical composition of epitaxially grown silicon (Si) and has alternating strains between a tensile strain and a compressive strain. A method of manufacturing the semiconductor structure is also provided.

Transdermal microneedles continuous monitoring system is provided. The continuous system monitoring includes a substrate, a microneedle unit, a signal processing unit and a power supply unit. The microneedle unit at least comprises a first microneedle set used as a working electrode and a second microneedle set used as a reference electrode, the first and second microneedle sets arranging on the substrate. Each microneedle set comprises at least a microneedle. The first microneedle set comprises at least a sheet having a through hole on which a barbule forms at the edge. One of the sheets provides the through hole from which the barbules at the edge of the other sheets go through, and the barbules are disposed separately.

A method and apparatus for forming a super-lattice structure on a substrate is described herein. The super-lattice structure includes a plurality of silicon-germanium layers and a plurality of silicon layers disposed in a stacked pattern. The methods described herein produce a super-lattice structure with transition width of less than about 1.4 nm between each of the silicon-germanium layers and an adjacent silicon layer. The methods described herein include flowing one or a combination of a silicon containing gas, a germanium containing gas, and a halogenated species.