Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
1998-07-29
2001-02-27
Jackson, Jr., Jerome (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S433000, C257S466000
Reexamination Certificate
active
06194771
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application claims the priority of Application No. H09-323442, filed Nov. 25, 1997 in Japan, the subject matter of which is incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor light-receiving device, and more particularly to, a side-(wall) surface-incident type of semiconductor light-receiving device for flat surface mounting, used for 1 &mgr;m band optical communication and the like.
BACKGROUND OF THE INVENTION
In general, a conventional semiconductor light-receiving device has a pin junction epi-wafer that includes an n-type buffer layer, an I-type light absorbing layer and a p-type cap layer laminated on a semiconductor substrate. In a semiconductor light-receiving device, disclosed in Japanese Laid open patent publication H7-202263, a light-receiving section is formed on a semiconductor substrate by shaping layered structure into a preferable shape.
One side-(wall) surface of the light-receiving section is a light-receiving surface, which is arranged vertical to the upper surface of the semiconductor substrate. An electrode is formed on the p-type cap layer of the light-receiving section; and an electrode is also formed on the back surface of the substrate.
In the semiconductor light-receiving device, light is not wave-guided to the I-type light absorbing layer inside the device. Therefore, the coupling efficiency of light cannot be improved and the density of the electric charge becomes high only around the light-receiving surface. As a result, a deterioration of the signal frequencies is extracted through the buffer layer or the cap layer. Providing a wave-guiding channel structure having a wave-guiding channel may solve this problem. The wave-guide channel structure wave-guides light to the I-type light absorbing layer inside the device; however, the application of the wave-guiding channel structure significantly increases the manufacturing cost of semiconductor light-receiving devices and is thus impractical.
The light-receiving surface may be curved to improve the coupling efficiency of this semiconductor light-receiving device, thus enlarging the exposed area of the I-type light absorbing layer relative to the light-receiving surface. Even though, however, an improvement in the coupling efficiencies is attempted by increasing the exposed area of the I-type light absorbing layer relative to the light-receiving surface with e.g., the curved light-receiving surface, the coupling efficiency is still small and there is still technical dissatisfaction over a deterioration of frequencies.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to provide a semiconductor light-receiving device, in which a high coupling efficiency is obtained and a frequency deterioration is minimized.
According to a first aspect of the invention, a semiconductor light-receiving device includes a light-receiving section that receives an input light. The light-receiving section includes a light-receiving surface to which the input light is directed, a groove extending vertically into the light-receiving surface, and a thin film coated on the inside wall of the groove.
In the semiconductor light-receiving device, the thin film may be formed to have a refractive index that is smaller than that of a light absorbing layer and have a photoluminescence wavelength that is shorter than that of the light absorbing layer.
In the above-described first aspect of the invention, an input light reaches the light-receiving surface of the light-receiving section. The light is absorbed by the light absorbing layer of the light-receiving surface, while the light reached the groove is wave-guided to the light absorbing layer by the thin film.
According to a second aspect of the invention, a semiconductor light-receiving device includes a light-receiving section that receives an input light. The light-receiving section includes a light-receiving surface to which the input light is directed; and a groove extending vertically into the light-receiving surface. The groove is provided with a mesa surface on its inside wall.
According to a third aspect of the invention, a semiconductor light-receiving device includes a light-receiving section that receives an input light; and a resin member covering the light-receiving section. The light-receiving section includes a light-receiving surface to which the input light is directed; a groove extending vertically into the light-receiving surface; and an inserted material filled in the groove to wave-guide the input light into the light-receiving section. The inserted material has a refraction index smaller than that of the resin member.
In the above-described third aspect of the invention, the input light provided from outside is refracted by the resin member, and reaches the light-receiving surface and the inserted material (wave-guiding channel) in the groove. The inserted material refracts the light and guides it to the side (wall) surfaces of the groove, thus guiding the light to the light absorbing layer in the side (wall) surface.
In each aspect of the invention, the groove may be designed to have a mesa surface on its inside wall, so that the input light is refracted at the mesa surface, and enters the light absorbing layer.
The groove may be arranged at the center of the light-receiving surface, so that coupling efficiency is highest around the groove when an optical fiber is aligned relative to the groove. Therefore, the alignment of the optical fiber is automatically conducted in a preferable manner.
Additional objects, advantages and novel features of the invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
REFERENCES:
patent: 3150999 (1964-09-01), Rudenberg et al.
patent: 4698129 (1987-10-01), Puretz et al.
patent: 5032879 (1991-07-01), Buchmann et al.
patent: 5258991 (1993-11-01), Peterson
patent: 5374588 (1994-12-01), Moon
patent: 5438208 (1995-08-01), Takemoto
patent: 5619518 (1997-04-01), Horie et al.
patent: 5665985 (1997-09-01), Iwata
patent: 5920587 (1999-07-01), Narui et al.
patent: 07202263 (1995-08-01), None
Sze, Physics of Semiconductor Devices, John Wiley & Sons, 1981.
Furukawa Ryozo
Kato Masanobu
Baumeister Bradley W.
Jackson, Jr. Jerome
Jones Volentine, L.L.C.
OKI Electric Industry Co., Ltd.
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