The gallium arsenide single crystal substrate has a circular main surface, and when the diameter of the main surface of the gallium arsenide single crystal substrate is represented by D and the number of etch pits formed on the main surface by immersing the gallium arsenide single crystal substrate in molten potassium hydroxide at 500° C. for 10 minutes is counted, the number C.sub.1 of etch pits in a first circular region having a diameter of 0.2D around the center of the main surface is 0 or more and 10 or less.

The invention discloses a device and a method for continuous VGF crystal growth through reverse injection synthesis, relating to a device for preparing a semiconductor crystal and growing a single crystal, in particular to a method and a device for continuously growing the crystal in situ by using a VGF method and reverse injection synthesis. The device includes a furnace body, a crucible, a heat preservation system, a heating system, a temperature control system and an gas pressure regulation system, wherein the crucible is arranged in the furnace body, has a synthesis unit at its upper part, and has a crystal growth unit and a seed crystal unit at its lower part, and the synthesis unit is communicated with the crystal growth unit through capillary pores. Red phosphorus and boron oxide are put into the growth unit, indium and boron oxide are put into the synthesis unit, solid seed crystals are put into the seed crystal unit, and temperature and pressure are controlled to accomplish material synthesis and in-situ crystal growth. According to the invention, the capillary pores are used, the temperature and the pressure are controlled, the phosphorus bubbles rise to the indium melt in the material synthesis stage, rendering a full fusion of the two substances, and after the phosphorus gasification, the indium-phosphorus melt drops into the growth unit to finish the in-situ growth of the crystal.

The invention discloses a device and a method for continuous VGF crystal growth through reverse injection synthesis, relating to a device for preparing a semiconductor crystal and growing a single crystal, in particular to a method and a device for continuously growing the crystal in situ by using a VGF method and reverse injection synthesis. The device includes a furnace body, a crucible, a heat preservation system, a heating system, a temperature control system and an gas pressure regulation system, wherein the crucible is arranged in the furnace body, has a synthesis unit at its upper part, and has a crystal growth unit and a seed crystal unit at its lower part, and the synthesis unit is communicated with the crystal growth unit through capillary pores. Red phosphorus and boron oxide are put into the growth unit, indium and boron oxide are put into the synthesis unit, solid seed crystals are put into the seed crystal unit, and temperature and pressure are controlled to accomplish material synthesis and in-situ crystal growth. According to the invention, the capillary pores are used, the temperature and the pressure are controlled, the phosphorus bubbles rise to the indium melt in the material synthesis stage, rendering a full fusion of the two substances, and after the phosphorus gasification, the indium-phosphorus melt drops into the growth unit to finish the in-situ growth of the crystal.

Crystal nucleation, and associated articles, systems, and methods, are generally described.

Methods and systems for low etch pit density 6 inch semi-insulating gallium arsenide wafers may include a semi-insulating gallium arsenide single crystal wafer having a diameter of 6 inches or greater without intentional dopants for reducing dislocation density, an etch pit density of less than 1000 cm.sup.2, and a resistivity of 110.sup.7 -cm or more. The wafer may have an optical absorption of less than 5 cm.sup.1 less than 4 cm.sup.1 or less than 3 cm.sup.1 at 940 nm wavelength. The wafer may have a carrier mobility of 3000 cm.sup.2/V-sec or higher. The wafer may have a thickness of 500 m or greater. Electronic devices may be formed on a first surface of the wafer. The wafer may have a carrier concentration of 1.110.sup.7 cm.sup.3 or less.

Crystal nucleation, and associated articles, systems, and methods, are generally described.

Crystal nucleation, and associated articles, systems, and methods, are generally described.

In a gallium arsenide crystal body, an etching pit density of the gallium arsenide crystal body is more than or equal to 10 cm.sup.2 and less than or equal to 10000 cm.sup.2, and an oxygen concentration of the gallium arsenide crystal body is less than 7.010.sup.15 atoms.Math.cm.sup.3. In a gallium arsenide crystal substrate, an etching pit density of the gallium arsenide crystal substrate is more than or equal to 10 cm.sup.2 and less than or equal to 10000 cm.sup.2, and an oxygen concentration of the gallium arsenide crystal substrate is less than 7.010.sup.15 atoms.Math.cm.sup.3.

Methods and systems for low etch pit density 6 inch semi-insulating gallium arsenide wafers may include a semi-insulating gallium arsenide single crystal wafer having a diameter of 6 inches or greater without intentional dopants for reducing dislocation density, an etch pit density of less than 1000 cm.sup.2, and a resistivity of 110.sup.7 -cm or more. The wafer may have an optical absorption of less than 5 cm.sup.1 less than 4 cm.sup.1 or less than 3 cm.sup.1 at 940 nm wavelength. The wafer may have a carrier mobility of 3000 cm.sup.2/V-sec or higher. The wafer may have a thickness of 500 m or greater. Electronic devices may be formed on a first surface of the wafer. The wafer may have a carrier concentration of 1.110.sup.7 cm.sup.3 or less.

Methods and systems for low etch pit density gallium arsenide crystals with boron dopant may include a gallium arsenide single crystal wafer having boron as a dopant, an etch pit density of less than 500 cm.sup.2, and optical absorption of 6 cm.sup.1 or less at 940 nm. The wafer may have an etch pit density of less than 200 cm.sup.2. The wafer may have a diameter of 6 inches or greater. The wafer may have a boron concentration between 110.sup.19 cm.sup.3 and 210.sup.19 cm.sup.3. The wafer may have a thickness of 300 m or greater. Optoelectronic devices may be formed on a first surface of the wafer, which may be diced into a plurality of die and optical signals from an optoelectronic device on one side of one of the die may be communicated out a second side of the die opposite to the one side.