Abstract: A method for producing a semiconductor device comprises the steps of: preparing a III.sub.b -V.sub.b group compound single crystalline semiconductor substrate produced by a liquid encapsulated Czochralski process, the single crystalline semiconductor substrate having a carbon concentration of 1.times.10.sup.15 cm.sup.-3 or less, implanting conductive impurity ions into the single crystalline semiconductor substrate and then annealing, and a semiconductor device produced by this method.

Abstract: In an epitaxial wafer comprising of a single crystalline substrate, a p type gallium aluminum arsenide mixed crystalline layer and n type gallium aluminum arsenide mixed crystalline layer having an indirect transition type band structure. The p type gallium aluminum arsenide mixed crystalline layer consists of a gallium aluminum arsenide mixed crystalline layer having a direct transition type band structure, positioned about 3 to 10 .mu.m from the pn junction and a gallium aluminum arsenide mixed crystalline layer having an indirect transition type band structure. The aluminum arsenide mixed crystal ratio in the gallium aluminum arsenide is exponentially and gradually changed in the region between the direct transition type layer and the indirect transition type layer.

Abstract: An epitaxial wafer for producing arrays of GaAsP-LEDs comprises, in the GaAs.sub.1-x P.sub.x layer with varying X, a layer region(s) with a discontinuous variance of x along the thickness of the GaAs.sub.1-x P.sub.x layer. This layer region(s) contribute to a uniformity in the brightness of the light emission of LEDs formed in the epitaxial wafer.

Abstract: In the boat growth method of the IIIb-Vb group compound, the quartz boat is tridymitized on at least the surface thereof so as to prevent wetting of the boat due to the melt of the compound and hence to enhance the yield of a single crystal.

Abstract: In a GaAs epitaxial wafer including, for example, two epitaxial layers having high and low carrier concentrations, the carrier concentration of the low carrier concentration layer is liable to greatly vary, so that wafers suitable for FETs and Schottky barrier diodes operated at UHF and SHF are produced at only a low yield. This drawback is eliminated by adjusting the heating temperature of GaAs substrate to 690.degree. to 730.degree. C. during the growth of the low carrier concentration layer.

Abstract: The reproducibility of Te doping in III-V group compounds is improved by using as the dopant a III-V group compound containing Te at a concentration of at least 1.times.10.sup.17 cm.sup.-3.

Abstract: The present invention relates to a wafer for use in the production of an infrared LED. Conventionally, infrared LEDs are produced by using an epitaxial wafer comprising P- and N-type GaAs epitaxial layers. The wafer according to the present invention is characterized by having a P-type Ga.sub.1-x Al.sub.x As epitaxial layer and improves the output power of infrared LEDs. The epitaxial layers according to the present invention are (1) a 20-100 .mu.m thick N-type GaAs epitaxial layer consisting of N-type GaAs doped with Si and having a carrier concentration in the range of from 1.0.times.10.sup.17.cm.sup.-3 to 2.0.times.10.sup.18.cm.sup.-3, (2) a 10-80 .mu.m thick P-type GaAs epitaxial layer consisting of P-type GaAs doped with Si and having a carrier concentration in the range of from 1.0.times.10.sup.17.cm.sup.-3 to 5.0.times.10.sup.18.cm.sup.-3, and (3) a 5-90 .mu.m thick mixed crystal layer consisting of P-type Ga.sub.1-x Al.sub.x As mixed crystal and having a carrier concentration of from 1.0.times.10.sup.

Abstract: An epitaxial wafer of a compound semiconductor comprising a single crystalline semiconductor substrate consisting of GaP and an active layer consisting of GaAs.sub.1-x P.sub.x, having a mixed crystal ratio (x) in the range of from 0.5 to 1 is used for an LED. According to the present invention, between the single crystalline semiconductor substrate and the active layer, a light-absorbing layer consisting of GaAs.sub.1-x P.sub.x having the mixed crystal ratio (x) smaller than that of the active layer, is formed to suppress the reflection of light from the surface of the substrate.

Abstract: When the growth of a single crystalline III.sub.b -V.sub.b group compound is carried out employing the horizontal Bridgeman method or the gradient freeze method, it is likely that polycrystals will be grown, crystal defects will form, and the distribution of impurities will not be uniform, especially if the diameter of the single crystal is large. In the present invention, the cooling rate of the melt is controlled in an inconstant manner. Namely, crystal growth is interrupted at least once and/or the cooling rate at an earlier growth period is controlled at a high value. From 40 to 65% of the total melt crystallizes at the time when 30% of the total time required for growth has elapsed. The high yield of a single crystal is attained according to the present invention.