Indium phosphide substrate and indium phosphide monocrystal and method of manufacturing thereof

An indium phosphide substrate containing iron or tin as a dopant, comprising:

• an average dislocation density value of a wafer being less than 2000 cm−2;
• a ratio of the difference between a maximum value and a minimum value with respect to an average value of dopant concentration in said wafer being 30% or less;
• a substantially uniform distribution of dopant concentration in the depth direction of said wafer.

An indium phosphide substrate containing sulfur or zinc as a dopant and having a diameter greater than or equal to 100 mm, comprising:

• an average dislocation density value of a wafer being less than 5000 cm−2;
• a ratio of the difference between a maximum value and a minimum value with respect to an average value of dopant concentration in said wafer being 30% or less;
• a substantially uniform distribution of said dopant concentration in the depth direction of said wafer.

An indium phosphide substrate containing sulfur or zinc as a dopant and having a diameter greater than or equal to 100 mm, comprising:

• an average dislocation density value of a wafer being less than 2000 cm−2;
• a ratio of the difference between a maximum value and a minimum value with respect to an average value of dopant concentration in said wafer being 30% or less;
• a substantially uniform distribution of said dopant concentration in the depth direction of said wafer.

An indium phosphide crystal containing tin as a dopant, wherein:

• a direction of growth has a <100> orientation;
• and
• an average dislocation density value on a (100) plane, which is perpendicular to said growth direction, is less than 5000 cm−2.

An indium phosphide crystal containing iron or tin as a dopant, wherein:

• a direction of growth has a <100> orientation;
• and
• an average dislocation density value on a (100) plane, which is perpendicular to said growth direction, is less than 2000 cm−2.

An indium phosphide crystal containing sulfur or zinc as a dopant and having a diameter of 100 mm or more, wherein:

• a direction of growth has a <100> orientation;
• an average dislocation density value on a (100) plane, which is perpendicular to said growth direction, is less than 5000 cm−2.

An indium phosphide crystal containing sulfur or zinc as a dopant and having a diameter of 100 mm or more, wherein:

• a direction of growth has a <100> orientation;
• and
• an average dislocation density value on a (100) plane, which is perpendicular to said growth direction, is less than 2000 cm−2.

An indium phosphide crystal containing iron as a dopant, wherein:

• a direction of growth has a <100> orientation;
• and
• an average dislocation density value on a (100) plane, which is perpendicular to said growth direction, is less than 2500 cm−2.

A method for manufacturing an indium phosphide monocrystal containing a dopant, comprising:

• placing a seed crystal, which has a cross-sectional area of 15% to 98% of a cross-sectional area of a crystal body, has an average dislocation density of less than 5000 cm−2 and has a substantially constant cross-sectional area along a length direction, at a lower end of a growth container so that direction of growth of said crystal is <100> oriented, said growth container including a seed crystal housing region having a substantially constant cross-sectional area, a crystal body housing region having a cross-sectional area larger than that of the seed crystal housing region, and a tapering region between the seed crystal housing region and the crystal body housing region;
• placing said growth container containing said seed crystal, indium phosphide raw material, dopant, and boron oxide in a crystal growth chamber, and raising the temperature to at or above the melting point of indium phosphide;
• after heating and melting boron oxide, indium phosphide raw material, dopant, and a portion of said seed crystal, lowering the temperature of said growth container in order to grow a monocrystal with a <100> orientation in a longitudinal direction of said growth container.