Apparatus and method for measuring semiconductor carrier lifetime

Patent metadata

Field	Value
Publication number	US-9279762-B2
Application number	US-201013500305-A
Country	US
Kind code	B2
Filing date	Oct 1, 2010
Priority date	Oct 6, 2009
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

In a semiconductor carrier lifetime measuring apparatus A 1 of the present invention, at least two types of light having mutually different wavelengths are irradiated onto a semiconductor X to be measured, a predetermined measurement wave is irradiated onto the semiconductor X to be measured, a reflected wave of the measurement wave that has been reflected by the semiconductor X to be measured or a transmitted wave of the measurement wave that has transmitted through the semiconductor X to be measured is detected, and the carrier lifetime in the semiconductor X to be measured is obtained based on the detection results so as to minimize the error. Accordingly, the semiconductor carrier lifetime measuring apparatus A 1 configured as described above can more accurately measure the carrier lifetime.

First claim

The invention claimed is:

1. A semiconductor carrier lifetime measuring apparatus, comprising:
a light irradiation unit which irradiates at least two types of light having mutually different wavelengths on a semiconductor to be measured;
a measurement wave irradiation unit which irradiates a predetermined measurement wave onto the semiconductor to be measured; and
a detection/calculation unit which detects a reflected wave of the measurement wave that has been reflected by the semiconductor to be measured or a transmitted wave of the measurement wave that has transmitted through the semiconductor to be measured, and which obtains a carrier lifetime in the semiconductor to be measured based on the detection results so as to minimize any error;
wherein
the detection/calculation unit comprises:
a detection unit which detects a reflected wave of the measurement wave that has been reflected by the semiconductor to be measured or a transmitted wave of the measurement wave that has transmitted through the semiconductor to be measured; and
a calculation unit which obtains a carrier lifetime in the semiconductor to be measured based on a first difference in a temporal relative change of the reflected wave or the transmitted wave detected by the detection unit as a result of the light irradiation unit irradiating the at least two types of light onto the semiconductor to be measured and the measurement wave irradiation unit irradiating the measurement wave onto the semiconductor to be measured when the semiconductor to be measured is in a first surface recombination velocity condition, and based on a second difference in a temporal relative change of the reflected wave or the transmitted wave detected by the detection unit as a result of the light irradiation unit irradiating the at least two types of light onto the semiconductor to be measured and the measurement wave irradiation unit irradiating the measurement wave onto the semiconductor to be measured when the semiconductor to be measured is in a second surface recombination velocity condition which is different from the first surface recombination velocity condition.

2. The semiconductor carrier lifetime measuring apparatus according to claim 1 ,
wherein the at least two types of light are a first light having a wavelength of an infrared region and a second light having a wavelength of an ultraviolet region.

3. The semiconductor carrier lifetime measuring apparatus according to claim 1 , wherein the at least two types of light are a first light having a wavelength of an infrared region and a third light having a wavelength of a visible region.

4. The semiconductor carrier lifetime measuring apparatus according to claim 1 , further comprising:
a surface recombination velocity condition changing unit which causes the semiconductor to be measured to change from the first surface recombination velocity condition to the second surface recombination velocity condition.

5. The semiconductor carrier lifetime measuring apparatus according to claim 4 ,
wherein the surface recombination velocity condition changing unit is a corona discharge application unit which applies a corona discharge to a measurement wave irradiated region of the semiconductor onto which a measurement wave is irradiated by the measurement wave irradiation unit.

6. The semiconductor carrier lifetime measuring apparatus according to claim 4 , wherein the semiconductor to be measured is in a condition of being provided with a natural oxide film as the first surface recombination velocity condition.

7. The semiconductor carrier lifetime measuring apparatus according to claim 1 , further comprising:
a power-generating irradiation unit which irradiates a power-generating light onto the semiconductor to be measured.

8. A semiconductor carrier lifetime measuring method, comprising:
a light irradiation step of irradiating at least two types of light having mutually different wavelengths on a semiconductor to be measured;
a measurement wave irradiation step of irradiating a predetermined measurement wave onto the semiconductor to be measured; and
a detection/calculation step of detecting a reflected wave of the measurement wave that has been reflected by the semiconductor to be measured or a transmitted wave of the measurement wave that has transmitted through the semiconductor to be measured, and obtaining a carrier lifetime in the semiconductor to be measured based on the detection results so as to minimize any error;
wherein
the detecting/calculation step comprises:
a detection step of detecting a reflected wave of the measurement wave that has been reflected by the semiconductor to be measured or a transmitted wave of the measurement wave that has transmitted through the semiconductor to be measured; and
a calculation step of obtaining a carrier lifetime in the semiconductor to be measured based on a first difference in a temporal relative change of the reflected wave or the transmitted wave detected in the detection step as a result of the at least two types of light being irradiated onto the semiconductor to be measured in the light irradiation step and the measurement wave being irradiated onto the semiconductor to be measured in the measurement wave irradiation step when the semiconductor to be measured is in a first surface recombination velocity condition, and a second difference in a temporal relative change of the reflected wave or the transmitted wave detected in the detection step as a result of the at least two types of light being irradiated onto the semiconductor to be measured in the light irradiation step and the measurement wave being irradiated onto the semiconductor to be measured in the measurement wave irradiation step when the semiconductor to be measured is in a second surface recombination velocity condition which is different from the first surface recombination velocity condition.

9. The semiconductor carrier lifetime measuring method according to claim 8 , wherein, in the calculation step, a carrier lifetime in the semiconductor to be measured is obtained by obtaining a ratio of a diffusion coefficient and a surface recombination velocity in the semiconductor to be measured based on the first difference and the second difference.

10. A semiconductor carrier lifetime measuring method, comprising:
a first difference measuring step of measuring, by irradiating at least two types of light having mutually different wavelengths while irradiating a predetermined measurement wave onto a semiconductor to be measured when the semiconductor to be measured is in a first surface recombination velocity condition, a first difference of a temporal relative change of a reflected wave of the measurement wave that has been reflected by the semiconductor to be measured or a transmitted wave of the measurement wave that has passed through the semiconductor to be measured;
a first S/D calculation step of obtaining S/D in the first surface recombination velocity condition based on the first difference measured in the first difference measuring step when a surface recombination velocity in the semiconductor to be measured is defined as S and a diffusion coefficient is defined as D;
a diffusion coefficient calculation step of obtaining the diffusion coefficient D based on the S/D in the first surface recombination velocity condition obtained in the first S/D calculation step;
a surface recombination velocity condition changing step of causing the semiconductor to be measured to change from the first surface recombination velocity condition to a second surface recombination velocity condition that is different from the first surface recombination velocity condition;
a second difference measuring step

Assignees

• Hayashi Kazushi
• Takamatsu Hiroyuki
• Fukumoto Yoshito
• Sumie Shingo
• Kobe Steel Ltd
• Kobelco Res Inst Inc

Inventors

• Hayashi Kazushi
• Takamatsu Hiroyuki
• Fukumoto Yoshito
• Sumie Shingo

Classifications

• H10P74/207

  Electrical properties, e.g. testing or measuring of resistance, deep levels or capacitance-voltage characteristics · CPC title

• H10P74/00 Primary

  Testing or measuring during manufacture or treatment of wafers, substrates or devices · CPC title

• H01L2924/00

  Electricity · mapped topic

• H01L22/14

  Electricity · mapped topic

• G01N21/31

  Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} · CPC title