JPS6350077A - Semiconductor light receiving device - Google Patents

Abstract

PURPOSE:To extend a light receiving band width having excellent characteristics and stability, by absorbing the light which fluorescent substance film generates being excited by an incident light and the transmitted light through a light receiving surface, with a semiconductor substrate. CONSTITUTION:On a P<+>type Si substrate 1, the followings are formed; e P-type light absorbing region 2, a P-type avalanche region 3, an N<+>type diffusion region 4, an N-type guard ring region 5, a P<+>type channel stopper region 6, a fluorescent substance film 7, an SiO2 film 8, an N-side electrode 9 and a P-side electrode 10. As to the fluorescent substance film 7, a film made of, for example, SrS:Eu system fluorescent substance is arranged in a ring form. Based on the thickness of the film 7 and the like, the transmittance of incident light is selected, and thereby the light reception sensitivity characteristics are controlled.

Description

Detailed Description of the Invention [Summary] The present invention provides an St semiconductor light receiving device in which a phosphor film is disposed on the light receiving surface, and the phosphor film is excited by incident light to emit light and light generated. The light-receiving band is expanded by causing the semiconductor substrate to absorb the incident light that has passed through the light-receiving surface.

[Industrial application field]

The present invention relates to a semiconductor light-receiving device, and particularly to a structure of an St semiconductor light-receiving device whose light-receiving band is widened.

In various optical application systems such as optical communication, light receiving devices made of semiconductor materials that match the required light receiving band are used, but for example, test equipment requires a wider light receiving band than the bandwidth determined by the semiconductor material. The realization of this goal is strongly desired.

[Conventional technology]

Many structures have been developed for semiconductor photodetectors depending on the purpose, and Figure 3 shows a schematic side sectional view of a conventional example of a silicon (St) avalanche photodiode (APD) suitable for the visible to near-infrared band. .

In this conventional example, 21 is a p+ type Si substrate, 22 is a p-
23 is a p-type avalanche region, 24 is a di-type diffusion region, 25 is an n-type guard ring region, 26 is a p + type channel stopper region, 28 is a silicon dioxide (SiO
2) In the film, 29 is an n-side electrode, and 30 is a p-side electrode.

The conventional example uses Si as the semiconductor material, but it has a similar structure in which germanium (Ge) is used as the semiconductor material and the conductivity type of each region is reversed.
D is provided.

Compound semiconductor APDs such as those based on indium phosphide/indium gallium arsenide (InP/InGaAs) have been developed for the 1.3 to 1.6 band, which is suitable for transmission using silica-based optical fibers; Since the wavelength of the obtained light is determined by its bandgap, the quantum efficiency of the semiconductor light receiving device is controlled by the semiconductor material of the light absorption region, as illustrated in FIG.

In addition, the avalanche multiplication factor and multiplication noise are extremely important characteristics in APD, and these values are roughly as shown below.The 5i-APD has a high multiplication factor and low multiplication noise, and is stable. is also the best.

Si-ΔPD Ge-APD InGaA
s-APD multiplication factor M Maximum value 500-1000 50-100 ~
50 Usage value 50-200 ~10 4-5 Multiplication noise parameter 0.22-0.3 0.5-0.9 ~0.7 [Problem to be solved by the invention] The semiconductor photodetector device is However, for example, in a test device that targets various types of lasers, it is necessary to have a light receiving band that covers each semiconductor light receiving device as described above, and to have characteristics, stability, etc. There is a demand for a semiconductor light receiving device with excellent characteristics.

[Means for solving problems]

The problem is that a phosphor film is disposed on the light-receiving surface of a semiconductor substrate made of silicon, and the phosphor film is excited by the incident light and separates the light generated and the incident light that passes through the light-receiving surface. This problem is solved by a semiconductor light receiving device according to the present invention that absorbs light in a semiconductor substrate.

[For production]

The semiconductor light receiving device according to the present invention is, for example, the conventional example 5.
Light generated when incident light excites a phosphor film disposed on the light-receiving surface of a semiconductor substrate corresponding to an i-APD, in contact with or in a corner of the light-receiving surface, and extending over the entire surface or only in one part of the light-receiving surface. and the incident light that has passed through the light receiving surface.

By using, for example, a fluorescent material that generates visible light in response to incident light in the infrared band for this phosphor film, it becomes possible to receive light in the infrared band with a longer wavelength than the band that the Si light receiving device can originally receive. . Examples of such fluorescent materials include the following examples in which alkaline earth metals are added to transition metals.

Strontium (Sr) Selenium (Se): Thallium (
TI) system; emits visible light using infrared light with a wavelength of around 2 μm.

Strontium (Sr) Sulfur (S): Europium (E
u) System; emits visible light using infrared light with a wavelength of around 1 μm.

Conversely, by using a phosphor that generates visible light with a longer wavelength than the incident light in the phosphor film, it is also possible to receive light in a wavelength band shorter than the light receiving band originally available for the Si light receiving device.

〔Example〕

The present invention will be specifically explained below using examples.

FIG. 1 is a schematic perspective sectional view showing an embodiment of the present invention,
The upper part shows the light-receiving surface, and the lower part shows the side cross section.

In the figure, 1 is a p+ type Si substrate, 2 is a p- type light absorption region, 3 is a p-type avalanche region, 4 is a busy diffusion region, and 5 is a p-type light absorption region.
6 is an n-type guard ring region, 6 is an f-type channel stopper region, 7 is a phosphor film according to the present invention, 8 is a SiO□ film, 9 is an n-side electrode, and 10 is a p-side electrode.

In this embodiment, a film made of the SrS:Eu-based fluorescent material and having a thickness of about 0.5 to 1.0 mm is arranged in a ring shape as the phosphor film 7, and the quantum efficiency shown in FIG. I am getting .

Although the phosphor film 7 is ring-shaped in this embodiment, it is not necessary to provide any openings. In this case, the transmittance of incident light is selected depending on the thickness of the phosphor film 7, etc. to control the light-receiving sensitivity characteristics.

Further, although the above explanation refers to /IPD, the present invention is a p-4-n device which does not have an avalanche multiplication function on the semiconductor substrate
It is also applicable to photodiodes and the like.

〔Effect of the invention〕

As explained above, according to the present invention, the light receiving band is expanded based on the excellent characteristics and stability of the Si light receiving device.
For example, the scope of application in laser testing equipment, etc. will be expanded, and this will greatly contribute to the advancement of optical application systems.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective sectional view of an embodiment of the present invention, Fig. 2 is a diagram showing an example of quantum efficiency of the embodiment, Fig. 3 is a schematic side sectional view of a conventional example, and Fig. 4 is Si and Ge light reception. It is a figure showing an example of quantum efficiency of a device. In the figure, 2 is a p+ type St substrate, 2 is a p- type light absorption region, 3 is a p-type avalanche region, 4 is an f-type diffusion region, 5 is an n-type guard ring region, 6 is a p-type channel stopper v4 region , 7 is a phosphor film according to the present invention, 8 is a SiO□ film, 9 is an n-side electrode, and 10 is a p-side electrode. Tip example/) Schematic side sectional view Most 1 Figure θ, 4 θP /, 2 /6 2
0 wavelength Cp-) Schematic diagram of wrinkle transfer J (it・1 Town map) 3 Diagram wavelength (μ town 5 Create Ge receiver and equipment quantum rejection factor 4)

Claims (1)

[Claims] 1) A phosphor film is provided on a light-receiving surface of a semiconductor substrate made of silicon, and the phosphor film is excited by incident light to generate light and the light that passes through the light-receiving surface. A semiconductor light-receiving device characterized in that light is absorbed in the semiconductor substrate. 2) The semiconductor light-receiving device according to claim 1, wherein the phosphor film is made of a phosphor that generates visible light in response to incident light in an infrared band.