Photodetector inspection apparatus and photodetector inspection method

A photodetector inspection method for inspecting a back-incident type photodetector that receives laser light incident from the back surface side, the method comprising:

• a step of placing the back-incident type photodetector with the light receiving surface thereof in contact, on a device placement portion of a measurement stage formed of a material transparent to the laser light, the device placement portion being provided with anti-reflection films formed on the front surface side and on the back surface side, respectively and being configured to prevent reflection of the laser light;
• a step of emitting the laser light emitted from a light source unit through an optical fiber unit toward a portion opposed to the device placement portion on the back surface side of the measurement stage;
• and
• a step of measuring device characteristics of the back-incident type photodetector by contacting a probe with the front surface of the back-incident type photodetector, wherein
• the optical fiber unit comprising a polarization-maintaining optical fiber is rotated around the optical axis direction to emit the laser light with the polarization direction rotated, and polarization dependence of the device characteristics of the back-incident type photodetector is measured.

A photodetector inspection apparatus for inspecting a back-incident type photodetector configured to receive laser light incident from the back surface side comprising:

• a measurement stage comprising a region including a device placement portion for placing the back-incident type photodetector with the light receiving surface thereof in contact, the region being formed of a transparent member with respect to the laser light;
• anti-reflection films that are configured to prevent reflection of the laser light, the anti-reflection films are formed on the front surface of the device placement portion and on the front surface of a portion opposed to the device placement portion on the back surface side of the measurement stage, respectively;
• a light source unit that is configured to emit the laser light onto the light receiving surface provided on the back surface of the back-incident type photodetector and is capable of selecting either CW light or pulsed light from the laser light;
• and
• an optical fiber unit that is connected at one end to the light source unit and is configured to guide the laser light and to emit the laser light from the other end toward the portion opposed to the device placement portion;
• and
• a rotating mechanism for rotating the optical fiber unit comprising a polarization-maintaining type optical fiber around the optical axis direction.

A photodetector inspection method for inspecting a back-incident type photodetector that receives laser light incident from the back surface side, the method comprising:

• a step of placing the back-incident type photodetector with the light receiving surface thereof in contact, on a device placement portion of a measurement stage formed of a material transparent to the laser light, the device placement portion being provided with anti-reflection films formed on the front surface side and on the back surface side, respectively and being configured to prevent reflection of the laser light;
• a step of emitting the laser light emitted from a light source unit through an optical fiber unit toward a portion opposed to the device placement portion on the back surface side of the measurement stage;
• and
• a step of measuring device characteristics of the back-incident type photodetector by contacting a probe with the front surface of the back-incident type photodetector, wherein
• polarization dependence of the device characteristics of the back-incident type photodetector is measured by rotating a wavelength plate provided between a portion opposed to the device placement portion on the back surface side of the measurement stage and the other end of the optical fiber unit.

A photodetector inspection method for inspecting a back-incident type photodetector that receives laser light incident from the back surface side, the method comprising:

• a step of placing the back-incident type photodetector with the light receiving surface thereof in contact, on a device placement portion of a measurement stage formed of a material transparent to the laser light, the device placement portion being provided with anti-reflection films formed on the front surface side and on the back surface side, respectively and being configured to prevent reflection of the laser light;
• a step of emitting the laser light emitted from a light source unit through an optical fiber unit toward a portion opposed to the device placement portion on the back surface side of the measurement stage;
• and
• a step of measuring device characteristics of the back-incident type photodetector by contacting a probe with the surface side of the back-incident type photodetector, wherein
• temperature dependence of the device characteristics of the back-incident type photodetector is measured by controlling the temperature of the back-incident type photodetector mounted on the device placement portion using a temperature control device provided on the measurement stage.