Silicon semiconductor substrate and process for producing the same

A semiconductor substrate comprising

• a substrate having a surface, a center, and a thickness between said surface and said center;
• an oxygen concentration at the center of the thickness of the substrate being up to 9.5×1017 atoms/cm3, after said substrate is heat-treated in a non-oxidizing atmosphere;
• said substrate having a locally densified portion produced by nitrogen segregation and exhibiting a signal strength at least two times an average signal strength at a depth of at least 12 μm below the surface thereof when measuring a concentration of nitrogen by secondary ion mass-spectroscopy (SIMS);
• and
• said substrate having a depth of a denuded zone of a void defect being at least 12 μm and a crystal defect density of oxygen precipitates at the center of the thickness thereof being at least 5×108/cm3.

A process for producing a silicon semiconductor substrate, comprising

• obtaining a silicon semiconductor substrate, having an oxygen concentration of up to 9.5×1017 atoms/cm3 and being obtained from a silicon single crystal;
• said silicon single crystal grown by using a silicon melt solution containing at least 5×1017 atoms/cm3 and up to 1.5×1019 atoms/cm3 of nitrogen through a method selected from the group consisting of Czochralski method and a magnetic field-applied Czochralski method;
• heat-treating said substrate for at least one hour at a temperature of at least 1200° C. in a non-oxidizing atmosphere;
• and
• cooling said substrate at a cooling rate of at least 5° C./minute at a temperature of 1100° C.

A process for producing a silicon semiconductor substrate, comprising

• obtaining a silicon semiconductor substrate, having an oxygen concentration of up to 9.5×1017 atoms/cm3 and being obtained from a silicon single crystal;
• said silicon single crystal grown by using a silicon melt solution containing at least 2×1017 atoms/cm3 and up to 1.5×1019 atoms/cm3 of nitrogen through a method selected from the group consisting of Czochralski method and a magnetic field-applied Czochralski method;
• heat-treating said substrate for at least one hour at a temperature of at least 1200° in a non-oxidizing atmosphere;
• and
• cooling said substrate at a cooling rate of at least 5° C./minute at a temperature of 1100° C.

A process for producing a silicon semiconductor substrate, comprising

• obtaining a silicon semiconductor substrate, having an oxygen concentration of up to 8.5×1017 atoms/cm3 and being obtained from a silicon single crystal;
• said silicon single crystal grown by using a silicon melt solution containing at least 1.×1018 atoms/cm3 and up to 1.5×1019 atoms/cm3 of nitrogen through a method selected from the group consisting of Czochralski method and a magnetic filed-applied Czochralski method;
• heat-treating said substrate for at least one hour at a temperature of at least 1200° C. in a non-oxidizing atmosphere;
• and
• cooling said substrate at a cooling rate of at least 1° C./minute and less than 5° C./minute at a temperature of 1100° C.