Nippon Mining Co., Ltd.

Japan Energy Corporation

Nihon Kogyo Kabushiki Kaisha

Nikko Kyodo Co., Ltd.

Osamu Oda

Keiji Kainosho

Haruhito Shimakura

Masayuki Uchida

Toyoaki Imaizumi

Kenji Kohiro

Arata Onozuka

Akio Koyama

Kenji Sato

Toshiaki Asahi

Masayuki Mori

Hironobu Sawatari

Hiromasa Yamamoto

A process for producing a semi-insulating InP single crystal and a semi-insulating InP single crystal are disclosed. The process comprises: a first step heat-treatment for heating an undoped InP single crystal having a concentration of a residual impurity of 0.05 ppmw or less containing at least one of Fe, Co and Cr, at a temperature of not less than 930.degree. C. and less than 1000.degree. C. in an atmosphere of phosphorous vapor pressure in the ampoule which is not less than a dissociation pressure of InP in equilibrium at the temperature and which is not more than 15 atm; and a second step heat-treatment for thereafter heating the InP single crystal at a temperature of not less than 662.degree. C. and less than 900.degree. C. in an atmosphere of phosphorous vapor pressure in the ampoule which is not less than 5 atm nor more than 50 atm. The semi-insulating InP single crystal substrate has a uniformity of mobility not more than 10% on the surface of the substrate.

Process for producing semi-insulating InP single crystal and

Method of growing a bulk crystal

A process for growing a multielement compound single crystal, includes the steps of placing a crucible holding a raw multielement compound of a predetermined set of composition ratios Y in a vertical crystal growing furnace having a heater, melting the raw multielement compound held in the crucible with the heater to produce a melt of the raw multielement compound in the crucible, controlling the output of the heater to grow a multielement compound single crystal of a predetermined set of composition ratios X from the melt so that the melt is solidified successively upwards from part of the melt in contact with the bottom of the crucible, and feeding to the melt as a solute at least one element of the raw multielement compound from above the level of the melt in the crucible so as to maintain the predetermined set of composition ratios X of the solute during growth of the multielement compound single crystal. The process can keep constant the composition of the grown multielement compound single crystal. The process is applicable to the growth of multielement compound semiconductor single crystals and multielement compound oxide single crystals.

Process for growing multielement compound single crystal

An undoped p-type GaAs epitaxial layer or an n-type GaAs epitaxial layer is grown on the surface of a wafer, and thereafter the wafer is annealed at a temperature which ranges from 800.degree. C. to 1,200.degree. C. and is equal to or higher than a predetermined critical temperature depending on the carrier concentration in the epitaxial layer before it is annealed. The epitaxial layer thus annealed is rendered semi-insulating without addition of any impurity. Accordingly, performances of an electronic device which incorporates such a wafer are improved.

Method of manufacturing compound semiconductor wafer

A method of fabricating a Schottky electrode by the adsorption of thin layer with not more than 10 monolayers of a metal whose oxide is stable on a III-V compound semiconductor substrate such as InP or on a substrate, the surface on which epitaxial layer is grown, and the successive oxidation of the thin metal film is disclosed. Since the generation of dangling bonds at the interface due to the elastic strain between the substrate and the metal oxide can be prevented, it becomes possible to obtain a Schottky electrode with a high Schottky barrier height and thus to fabricate MESFETs and Schottky diodes having good characteristics such as a small reverse leak current and a large break-down voltage.

Method of fabricating a compound semiconductor device

A semi-insulating InP single crystal, semiconductor device with a substrate of crystal and processes of producing the same are disclosed. Crystal is derived from an undoped InP single crystal intermediate. The intermediate has a concentration of all native Fe, Co and Cr of 0.05 ppmw. The crystal has a resistivity of 1.times.10.sup.6 .OMEGA..multidot.cm or more and a mobility of above 3,000 cm.sup.2 /V.multidot.s both at 300K. A process of producing the crystal includes a step of heat-treating the intermediate under 6 kg/cm.sup.2 of phosphorus vapor pressure. The produced semiconductor device is a MIS device operating in essentially the same high-speed manner as a HEMT.

Semi-insulating InP single crystals, semiconductor devices having

Process for producing a uniform oxide layer on a compound semiconductor

A semi-insulating InP single crystal, semiconductor device with a substrate of crystal and processes of producing the same are disclosed. The crystal is derived from an undoped InP single crystal intermediate. The intermediate has a concentration of all native Fe, Co and Cr of 0.05 ppmw or less. The crystal has a resistivity of 1.times.10.sup.6 .OMEGA..multidot.cm or more and a mobility of above 3,000 cm.sup.2 /V.multidot.s both at 300 K. A process of producing the crystal includes a step of heat-treating the intermediate under 6 kg/cm.sup.2 of phosphorus vapor pressure. The produced semiconductor device is a MIS device operating in essentially the same high-speed manner as a HEMT.

Semi-insulating INP single crystals, semiconductor devices having

A method for producing compound semiconductor single crystal substrates which comprises the following steps, wafers of a compound semiconductor single crystal grown by the LEC method are installed in an evacuated and sealed quartz ampoule and subjected to a first annealing step at the predetermined temperature for the predetermined period, then the wafers are gradually cooled down to room temperature at the predetermined cooling speed, the cooled wafers are then subjected to etching, the etched wafers are subjected to a second annealing step at the predetermined temperature for the predetermined period in a non-oxidizing atmosphere, and finally, the wafers are gradually cooled down to room temperature.

Method for producing compound semiconductor single crystal substrates

The present invention relates to a method for producing InP single crystals containing impurities such as Fe, Co, Ti, Cr or the like by cutting the single crystals into wafers or blocks and heat-treating the cut wafers or blocks at temperatures ranging from 400.degree. C. to 690.degree. C. Further, the invention is related to a method for producing compound semiconductor devices employing Fe-doped InP single crystals as the substrate of the device. In this method, the InP single crystals are cut into wafers and the cut wafers are heat-treated at temperatures ranging from 400.degree. C. to 690.degree. C. Further, the wafers are implanted with ions and heat-treated at 690.degree. C. or lower to activate the implanted ions. These methods ensure to produce the single crystals and the compound semiconductor devices which have superior electrical properties.

Method for producing compound semiconductor single crystals and method

A vapor-deposited film of selenium as a photoreceptor for electrophotography contains not more than 50 parts per million of oxygen. In producing the film, the oxygen content in the starting material selenium is controlled so that the resulting film contains oxygen within the specified range. The original oxygen content is reduced by vacuum distillation of the material selenium in a high vacuum, reduced-pressure distillation in high purity hydrogen, or preservation of the selenium shot in vacuo or in an inert gas. The starting material is obtained by mixing or melting selenium with a predetermined amount of selenium dioxide, or by carrying out vacuum distillation either of selenium at a vacuum degree of about 10.sup.-2 torr and thereby converting part of the material selenium into selenium dioxide, or of a mixture of selenium and a predetermined amount of selenium dioxide. The vacuum degree during the vapor deposition is controlled so that the oxygen content in the resulting film is 50 ppm or less.

Vapor-deposited film of selenium as photoreceptor for electrophotography

A vapor-deposited film of selenium or selenium alloy as a photoreceptor for electrophotography comprises selenium or a selenium alloy and phosphorus contained therein in an amount of not less the 0.5 ppm and adjusted to attain a desired contrast potential. The selenium alloy is selected from Se-Te, Se-As, Se-Bi, and Se-Sb alloys. The film is produced either by adding phosphorus to stock selenium or selenium alloy and then vacuum-depositing the phosphorus-containing selenium or selenium alloy or by simultaneously vapor-depositing selenium or selenium alloy and elemental phosphorus or a phosphorus compound.

Growing community of inventors

Toda, Japan

Osamu Oda