Abstract:
The invention inter alia relates to a method of fabricating a layer assembly comprising the steps of: arranging a first layer on top of a carrier; arranging a second layer on top of the first layer; locally modifying the material of the buried first layer and providing at least one modified section in the first layer, wherein the modified material changes or induces mechanical strain in a portion of the second layer which is arranged above the at least one modified section; after locally modifying the material of the buried first layer, depositing a third material on top of the second layer, at least one characteristic of the third material being sensitive to the local mechanical strain in the second layer.
Abstract:
An (AlInGaN) based semiconductor device, comprising a first layer that is a semipolar or nonpolar nitride (AlInGaN) layer having a lattice constant that is partially or fully relaxed, deposited on a substrate or a template, wherein there are one or more dislocations at a heterointerface between the first layer and the substrate or the template; one or more strain compensated layers on the first layer, for defect reduction and stress engineering in the device, that is lattice matched to a larger lattice constant of the first layer; and one or more nonpolar or semipolar (AlInGaN) device layers on the strain compensated layers.
Abstract:
An epitaxial structure for a Ill-Nitride based optical device, comprising an active layer with anisotropic strain on an underlying layer, where a lattice constant and strain in the underlying layer are partially or fully relaxed in at least one direction due to a presence of misfit dislocations, so that the anisotropic strain in the active layer is modulated by the underlying layer.
Abstract:
Ga(In)N -based laser structures and related methods of fabrication are proposed where Ga (In)N-based semiconductor laser structures are formed on AlN or GaN substrates (20) in a manner that addresses the need to avoid undue tensile strain in the semiconductor structure. In accordance with one embodiment of the present invention, a Ga (In)N-based semiconductor laser is provided on an AlN or GaN substrate provided with an AlGaN lattice adjustment layer (30) where the substrate (20), the lattice adjustment layer (30), the lower cladding region (60), the active waveguiding region (40), the upper cladding region (50), and the N and P type contact regions (70, 60) of the laser form a compositional continuum in the semiconductor laser. Additional embodiments are disclosed and claimed.
Abstract:
A semiconductor device comprises an active layer (350) and a cladding layer (370). An electron blocking layer (380) is at least partially disposed in a region between the active layer and the cladding layer and is configured to form a potential barrier to a flow of electrons from the active layer toward the cladding layer. The electron blocking layer comprises two elements from Group m of the periodic table and an element from Group V of the periodic table. One of the two elements from Group III of the periodic table has a concentration profile with a first portion that gradually increases in concentration in a direction away from the active layer toward the cladding layer and a second portion that gradually decreases in concentration between the first portion and the cladding layer.
Abstract:
A strain compensating structure (112) comprises a strain compensating layer (104) adjacent an oxide-forming layer (106). The strain compensating layer (104) compensates for the change in the lattice parameter due to oxidation of at least part of the oxide-forming layer (106).
Abstract:
A laser system having migration enhanced epitaxy grown substantially flat layers proximate to quantum wells of an active region. The flat layers may be grown at low temperature. This growth may result in flatter interfaces in the nitrogen containing quantum wells within the active region as well as lower trap densities in adjacent material. This may achieve a reduced trap density as well as reduced segregation resulting in a spectral luminescence profile revealing a single narrow peak with a high level of photoluminescence.
Abstract:
Methods and Systems producing flattening layers associated with nitrogen-containing quantum wells and to prevent 3-D growth of nitrogen containing layers using high As fluxes. MEE (Migration Enhanced Epitaxy) is used to flatten layers and enhance smoothness of quantum wells interfaces and to achieve narrowing of the spectrum of light emitted from nitrogen containing quantum wells. MEE is performed by alternately depositing single atomic layers of group III and V before, and/or after, and/or in-between quantum wells. Where GaAs is used, the process can be accomplished by alternately opening and closing Ga and As shutters in an MBE system, while preventing both from being open at the same time. Where nitrogen is used, the system incorporates a mechanical means of preventing nitrogen from entering the MBE processing chamber, such as a gate valve. The gate valve allows the nitrogen source to be completely cut-off from the chamber during non-nitrogen processing steps to achieve the flattening layers described herein. In at least nitrogen containing layers, 3-dimensional growth is also reduced by using high arsenic fluxes, and by using substantially As4 as the main constituent of the arsenic flux.