C30B29/44

DEVICE AND METHOD FOR CONTINUOUS VGF CRYSTAL GROWTH THROUGH ROTATION AFTER HORIZONTAL INJECTION SYNTHESIS

The invention provides a device and method for continuous VGF crystal growth through rotation after horizontal injection synthesis, and belongs to the technical field of semiconductor crystal synthesis and growth. According to the used technical scheme, the device comprises a furnace body, a synthesis and crystal growth system positioned in a furnace cavity, and a heating system, a temperature measuring system, a heat preservation system and a control system matched therewith, wherein the synthesis and crystal growth system comprises a crucible and a volatile element carrier arranged on a horizontal side of the crucible, and the volatile element carrier is communicated with the crucible through an injection pipe to realize horizontal injection synthesis; the furnace body has a rotational freedom degree by means of a matched rotating mechanism, so that after the direct horizontal injection synthesis of a volatile element and a pure metal element, the entire furnace body is controlled by the rotating mechanism to slowly rotate, such that a high-purity compound semiconductor crystal is prepared through continuous VGF crystal growth after crystal synthesis, and the condition that a seed crystal is molten by the pure metal before VGF crystal growth can be avoided; and the method has characteristics of simple steps, easy operation and control, and is suitable for the industrial production of semiconductor crystals.

METHOD FOR FABRICATING INGAP EPITAXIAL LAYER BY METAL ORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD)
20190164753 · 2019-05-30 ·

The present invention provides a method for fabricating an InGaP epitaxial layer by metal organic chemical vapor deposition (MOCVD). The method comprises: placing a silicon substrate in a reaction chamber; arranging the reaction chamber to have a first chamber temperature, and growing a first GaP layer with a first thickness on the Si substrate at the first chamber temperature; arranging the reaction chamber to have a second chamber temperature, and growing a second GaP layer with a second thickness on the first GaP layer at the second chamber temperature; arranging the reaction chamber to have a third chamber temperature for a first time interval, and then arranging the reaction chamber to have a fourth chamber temperature for a second time interval; and growing a multi-layered InGaP layer on the second GaP layer.

METHOD FOR FABRICATING INGAP EPITAXIAL LAYER BY METAL ORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD)
20190164753 · 2019-05-30 ·

The present invention provides a method for fabricating an InGaP epitaxial layer by metal organic chemical vapor deposition (MOCVD). The method comprises: placing a silicon substrate in a reaction chamber; arranging the reaction chamber to have a first chamber temperature, and growing a first GaP layer with a first thickness on the Si substrate at the first chamber temperature; arranging the reaction chamber to have a second chamber temperature, and growing a second GaP layer with a second thickness on the first GaP layer at the second chamber temperature; arranging the reaction chamber to have a third chamber temperature for a first time interval, and then arranging the reaction chamber to have a fourth chamber temperature for a second time interval; and growing a multi-layered InGaP layer on the second GaP layer.

METHOD OF PRODUCING LARGE EMI SHIELDED GaAs AND GaP INFRARED WINDOWS

A method of making GaP window slabs having largest dimensions of greater than 4 inches and GaAs IR window slabs having largest dimensions of greater than 8 inches, includes slicing and dicing at least one smaller GaAs or GaP single crystal boule, which can be a commercial boule, to form a plurality of rectangular slabs. The slabs are ground to have precisely perpendicular edges, which are polished to be ultra-flat and ultra-smooth, for example to a flatness of at least ?/10, and a roughness Ra of less than 10 nanometers. The slab edges are then aligned and fused via optical-contacting/bonding to create a large GaAs or GaP slab having negligible bond interface losses. A conductive, doped GaAs or GaP layer can be applied to the window for EMI shielding in a subsequent vacuum deposition step, followed by applying anti-reflection (AR) coatings to one or both of the slab faces.

METHOD OF PRODUCING LARGE EMI SHIELDED GaAs AND GaP INFRARED WINDOWS

A method of making GaP window slabs having largest dimensions of greater than 4 inches and GaAs IR window slabs having largest dimensions of greater than 8 inches, includes slicing and dicing at least one smaller GaAs or GaP single crystal boule, which can be a commercial boule, to form a plurality of rectangular slabs. The slabs are ground to have precisely perpendicular edges, which are polished to be ultra-flat and ultra-smooth, for example to a flatness of at least ?/10, and a roughness Ra of less than 10 nanometers. The slab edges are then aligned and fused via optical-contacting/bonding to create a large GaAs or GaP slab having negligible bond interface losses. A conductive, doped GaAs or GaP layer can be applied to the window for EMI shielding in a subsequent vacuum deposition step, followed by applying anti-reflection (AR) coatings to one or both of the slab faces.

METHOD OF PRODUCING LARGE GaAs AND GaP INFRARED WINDOWS

A method of growing large GaAs or GaP IR window slabs by HVPE, and in embodiments by LP-HVPE, includes obtaining a plurality of thin, single crystal, epitaxial-quality GaAs or GaP wafers, cleaving the wafers into tiles having ultra-flat, atomically smooth, substantially perpendicular edges, and then butting the tiles together to form an HVPE substrate larger than 4 inches for GaP, and larger than 8 inches or even 12 inches for GaAs. Subsequent HVPE growth causes the individual tiles to fuse by optical bonding into a large tiled single crystal wafer, while any defects nucleated at the tile boundaries are healed, causing the tiles to merge with themselves and with the slab with no physical boundaries, and no degradation in optical quality. A dopant such as Si can be added to the epitaxial gases during the final HVPE growth stage to produce EMI shielded GaAs windows.

METHOD OF PRODUCING LARGE GaAs AND GaP INFRARED WINDOWS

A method of growing large GaAs or GaP IR window slabs by HVPE, and in embodiments by LP-HVPE, includes obtaining a plurality of thin, single crystal, epitaxial-quality GaAs or GaP wafers, cleaving the wafers into tiles having ultra-flat, atomically smooth, substantially perpendicular edges, and then butting the tiles together to form an HVPE substrate larger than 4 inches for GaP, and larger than 8 inches or even 12 inches for GaAs. Subsequent HVPE growth causes the individual tiles to fuse by optical bonding into a large tiled single crystal wafer, while any defects nucleated at the tile boundaries are healed, causing the tiles to merge with themselves and with the slab with no physical boundaries, and no degradation in optical quality. A dopant such as Si can be added to the epitaxial gases during the final HVPE growth stage to produce EMI shielded GaAs windows.

METHOD OF OPTIMIZING THE EMI SHIELDING AND INFRARED TRANSPARENCY OF GaAs IR WINDOWS

A method of manufacturing a structurally competent, EMI-shielded IR window includes using a mathematical model that combines the Sotoodeh and Nag models to determine an optimal thickness and dopant concentration of a doped layer of GaAs or GaP. A slab of GaAs or GaP is prepared, and a doped layer of the same material having the optimal thickness and dopant concentration is applied thereto. In embodiments, the doped layer is applied by an HVPE method such as LP-HVPE, which can also provide enhanced GaAs transparency near 1 micron. The Drude model can be applied to assist in selecting an anti-reflective coating. If the model predicts that the requirements of an application cannot be met by a doped layer alone, a doped layer can be applied that exceeds the required IR transparency, and a metallic grid can be applied to improve the EMI shielding, thereby satisfying the requirements.

METHOD OF PRODUCING LARGE GaAs AND GaP INFRARED WINDOWS

IR window slabs of GaP greater than 4 inches diameter, and of GaAs greater than 8 inches diameter, are grown on a substrate using Hydride Vapor Phase Epitaxy (HVPE), preferably low pressure HVPE (LP-HVPE). Growth rates can be hundreds of microns per hour, comparable to vertical melt growth. GaAs IR windows produced by the disclosed method exhibit lower absorption than crystals grown from vertical melt near 1 micron, due to reduced impurities and reduced growth temperatures that limit the solubility of excess arsenic, and thereby reduce the EL2 defects that cause high absorption near one micron in conventional GaAs boules. Silicon wafers can be used as HVPE substrates. For GaAs, layers of GaAsP that vary from 0% to 100% As can be applied to the substrate. EMI shielding can be applied by adding a dopant during the final stage of growth to provide a conductive GaAs or GaP layer.

METHOD OF PRODUCING LARGE GaAs AND GaP INFRARED WINDOWS

IR window slabs of GaP greater than 4 inches diameter, and of GaAs greater than 8 inches diameter, are grown on a substrate using Hydride Vapor Phase Epitaxy (HVPE), preferably low pressure HVPE (LP-HVPE). Growth rates can be hundreds of microns per hour, comparable to vertical melt growth. GaAs IR windows produced by the disclosed method exhibit lower absorption than crystals grown from vertical melt near 1 micron, due to reduced impurities and reduced growth temperatures that limit the solubility of excess arsenic, and thereby reduce the EL2 defects that cause high absorption near one micron in conventional GaAs boules. Silicon wafers can be used as HVPE substrates. For GaAs, layers of GaAsP that vary from 0% to 100% As can be applied to the substrate. EMI shielding can be applied by adding a dopant during the final stage of growth to provide a conductive GaAs or GaP layer.