Freiberger Compound Materials Gmbh

Gunnar Leibiger

Frank Habel

Stefan Eichler

Berndt Weinert

Ferdinand Scholz

Peter Brückner

Stefan Hölzig

Stefan HÖLZIG

A III-V-, IV-IV- or II-VI-compound single crystal comprising III-, IV- or II-precipitates and/or unstoichiometrical III-V-, IV-VI-, or II-VI-inclusions, wherein concentration of the respective precipitates and/or inclusions is no more than 1×10cm.

Growth of A-B crystals without crystal lattice curvature

The present invention relates to a process for the production of III-V-, IV-IV- or II-VI-compound semiconductor crystals. The process starts with providing of a substrate with optionally one crystal layer (buffer layer). Subsequently, a gas phase is provided, which comprises at least two reactants of the elements of the compound semiconductor (II, III, IV, V, VI) which are gaseous at a reaction temperature in the crystal growth reactor and can react with each other at the selected reactor conditions. The ratio of the concentrations of two of the reactants is adjusted such that the compound semiconductor crystal can crystallize from the gas phase, wherein the concentration is selected that high, that crystal formation is possible, wherein by an adding or adjusting of reducing agent and of co-reactant, the activity of the III-, IV- or II-compound in the gas phase is decreased, so that the growth rate of the crystals is lower compared to a state without co-reactant. Therein, the compound semiconductor crystal is deposited at a surface of the substrate, while a liquid phase can form on the growing crystal. Further, auxiliary substances may be added, which can also be contained in the liquid phase, but is only incorporated in low amounts into the compound semiconductor crystal. Herein, 3D- and 2D-growth modes can be controlled in a targeted manner. The addition of auxiliary substances and the presence of a liquid phase favour these means. The product is a single crystal of the respective III-V-, IV-IV- or II-VI-compound semiconductor crystal, which, compared to respectively conventional compound semiconductor crystals has a lower concentration of inclusions or precipitates and nevertheless has no or only a very low curvature.

A semiconductor compound material, preferably a III-N-bulk crystal or a III-N-layer, is manufactured in a reactor by means of hydride vapor phase epitaxy (HVPE), wherein in a mixture of carrier gases a flow profile represented by local mass flow rates is formed in the reactor. The mixture can carry one or more reaction gases towards a substrate. Thereby, a concentration of hydrogen important for the reaction and deposition of reaction gases is adjusted at the substrate surface independently from the flow profile simultaneously formed in the reactor.

Method and device for manufacturing semiconductor compound materials by means of vapour phase epitaxy

A process for producing a doped III-N bulk crystal, wherein III denotes at least one element of the main group III of the periodic system, selected from Al, Ga and In, wherein the doped crystalline III-N layer or the doped III-N bulk crystal is deposited on a substrate or template in a reactor, and wherein the feeding of at least one dopant into the reactor is carried out in admixture with at least one group III material. In this manner, III-N bulk crystals and III-N single crystal substrates separated therefrom can be obtained with a very homogeneous distribution of dopants in the growth direction as well as in the growth plane perpendicular thereto, a very homogeneous distribution of charge carriers and/or of the specific electric resistivity in the growth direction as well as in the growth plane perpendicular thereto, and a very good crystal quality.

Process for the manufacture of a doped III-N bulk crystal and a free-standing III-N substrate, and doped III-N bulk crystal and free-standing III-N substrate as such

A process for preparing smoothened III-N, in particular smoothened III-N substrate or III-N template, wherein III denotes at least one element of group III of the Periodic System, selected from Al, Ga and In, utilizes a smoothening agent comprising cubic boron nitride abrasive particles. The process provides large-sized III-N substrates or III-N templates having diameters of at least 40 mm, at a homogeneity of very low surface roughness over the whole substrate or wafer surface. In a mapping of the wafer surface with a white light interferometer, the standard deviation of the rms-values is 5% or lower, with a very good crystal quality at the surface or in surface-near regions, measurable, e.g., by means of rocking curve mappings and/or micro-Raman mappings.

Process for smoothening III-N substrates

Embodiments of the invention relate to a process for producing a III-N bulk crystal, wherein III denotes at least one element selected from group III of the periodic system, selected from Al, Ga and In, wherein the III-N bulk crystal is grown by vapor phase epitaxy on a substrate, and wherein the growth rate is measured in real-time. By actively measuring and controlling the growth rate in situ, i.e. during the epitaxial growth, the actual growth rate can be maintained essentially constant. In this manner, III-N bulk crystals and individualized III-N single crystal substrates separated therefrom, which respectively have excellent crystal quality both in the growth direction and in the growth plane perpendicular thereto, can be obtained.

Growing community of inventors

Freiberg, Germany

Gunnar Leibiger