JPS61271886A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To obtain a device characterized by easy manufacture and a high speed switching function, by providing a PNP multilayer structure comprising three or more growing layers on a P-type semiconductor substrate, providing electrodes on the substrate, the uppermost N-type layer and the P-type layer immediately beneath the N-type layer, and using one of the N- and P-type growing layers wherein a junction part is present as an active region. CONSTITUTION:On a P-InP substrate 1, a P-InP buffer layer 2, an Sn doped InGaAsP active layer 3 and an N-InP clad layer 4 are formed. Thereafter, with an SiO2 having a width of 1.5mum as a mask, proton is projected on both sides of the growing layers, and a high-resistance current limiting region 5 is formed. After the SiO2 film is removed, a P-InP layer 6 and an N-InP layer 7 are sequentially grown. With an SiO2 film as a mask, e.g., Be ions are implanted so as to reach at least the layer 6, and a P<+> regions 8 are formed. Then electrode metal is evaporated on the substrate and N and P regions on the side of the growing layers. By using electrode isolating layers 9 of an SiO2 film, independent electrodes 10, 11 and 12 are formed. An element, which has a resonator with a length of about 250mum, is obtained by cleavage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor laser device having a switching function.

[Summary of the Disclosure] The present invention discloses a technology for realizing a semiconductor laser that is easy to manufacture and has a high-speed switching function by configuring a semiconductor laser and an electric element during growth and lamination in a semiconductor laser device. It is.

This summary is provided solely for the purpose of quickly accessing the technical content of the present invention, and does not have any influence on the technical scope of the present invention or the interpretation of rights.

[Prior Art] Optical signals in optical fiber transmission systems are often composed of a semiconductor laser and an electrical circuit for supplying electrical signals to and driving the laser. However, the laser and drive circuit are not monolithic. Integration into the optical fiber transmission system is not only attractive in terms of reliability and cost, but also very advantageous in increasing the modulation frequency.

FETs, transistors, etc. can be considered as electric elements formed on the same substrate. However, conventionally, these elements are formed separately from the semiconductor laser, so when integrating them, not only is the manufacturing process extremely complicated, but the yield of each other's characteristics is affected, making it difficult to match the characteristics. Very advanced manufacturing techniques were required to obtain such integrated devices.

[Problems to be Solved by the Invention] The present invention has been made to solve these conventional drawbacks, and it is possible to configure a semiconductor laser and an electric element in a single semiconductor device, which is easy to manufacture. An object of the present invention is to provide a semiconductor laser device having a high-speed switching function.

[Means for solving the problem] In the present invention, at least three
It has a pnpn multilayer structure consisting of growth layers, and electrodes are provided on the substrate, the uppermost n-type layer, and the p-type layer directly below the uppermost n-type layer, and the n-type and plJ
Either one of the growth layers is used as an active region.

[Function] With such a configuration, high-speed switching can be performed by applying a voltage to the electrode provided with the p◆ region.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an embodiment of the present invention in FIG. 0, where l is p
-1nP substrate, 2 is p-Ir+P bar''/77 layers, 3
is n-InGaAsP active layer, 4 is n-1nP clad layer, 5 is high resistance layer, 6 is p-1nP N, 7 is n
-1nP layer, 8 is a p+ desired region for injecting current into the p-1nP layer, 9 is a 5i02 film, IO is an electrode on the n-InP layer 7, 11 is an electrode on the p◆ region 8, 12 is a substrate This is the first electrode. To form this, proceed as follows.

A p -1nP buffer layer 2 (
Thickness 3ILm, Zn doped, 5 X 10' cm-
), composition wavelength 1.34m, carrier concentration 10"
ctg-” Sn-doped InGaAsP active layer 3 (
thickness 0.15#Lm), n-1nP cladding layer 4 (
After forming a 0.2 gm thick, Sn-doped, 1G" cm-3) growth layer, proton irradiation was performed on both sides of the growth layer using a 5iOz Ill with a width of 1.57 zm as a mask to form a high-resistance current limiting region 5. Form.

After removing the 5i02 film, a p-1nP layer 6 (thickness
1. OILm, Zn doped, 5 X 10” cm-
3) and n-1nPFJ7 (thickness 1.01h m,
Sn-doped, lXl0''cm-') are sequentially grown.

Furthermore, using 5i02 WA as a mask, at least the 6th
For example, Be ions are implanted so as to reach the layer to form a p+ region 8. After that, metals for electrodes are deposited on the n and p regions on the substrate side and the growth layer side, and independent electrodes 10, 11, 12 are formed using the electrode separation M9 of the 5i02 film.
form. And by cleavage, the resonator length is 250#
It is assumed that the element is L■.

The current-voltage characteristics in the embodiment of the present invention shown in FIG. 2 have a negative resistance region, as shown in FIG. Therefore, via electrode 11, a positive voltage (>0.5V)
When the voltage is applied, the above-mentioned element turns on and oscillates as a laser. At this time, the voltage between electrodes 10 and 12 is approximately 2.5V.
The current in the ON state is 100ss.

A light output of 15+sw can be achieved.

FIG. 4 is another embodiment of the present invention, in which p -1 of FIG.
Instead of the nP layer 6, a p layer whose composition wavelength is longer than that of the active layer 3 is used.
-1nGaAsP F713 (thickness 1.OJL m,
Zn-doped, 5×10110l6', composition wavelength 1.32 gm) was grown. Since a part of the spontaneously emitted light in the laser oscillation state is absorbed by the layer 13, the laser oscillation is maintained even when the positive voltage of the electrode 11 is turned off, making it possible to realize an optical memory. Note that in order to stop laser oscillation, it is sufficient to apply a negative voltage to the electrode 11. FIG. 5 shows an example of a photoresponse waveform using the device shown in FIG. 4.

FIG. 6 is a cross-sectional view along the central resonator direction of another embodiment of the present invention, using a substrate on which a second-order diffraction grating 14 (4800 pitches, 1000 pitches) is formed on the surface. Manufactured. This diffraction grating allows part of the laser light to
The amount of light taken out in the vertical direction and absorbed by the calendar 13 is approximately 100 times greater than in the case of the element shown in FIG. Therefore, assuming that the number of carriers generated by regular use is the same, the thickness of 913 in FIG. 6 can be reduced to 0.2 gm, and the switching time can be shortened to about 172.5 gm.

The second-order diffraction grating may be provided within the buffer layer 2 instead of on the surface of the substrate l.

Although the current limiting region 5 has been described as being formed by proton irradiation, it is also possible to form it by crystal growth of a high-purity growth layer and a semi-insulating layer such as Fe-doped.

Furthermore, although the above embodiments have been explained using InP-based semiconductor materials, it is clear that GaAa-based semiconductor materials and conductive materials can also be applied.

[Effects of the Invention] As described above, since the semiconductor laser and the electric element are formed during growth and lamination, there is an advantage that the semiconductor laser is easy to manufacture and can have a high-speed switching function.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a diagram showing the driving method of the embodiment, FIG. 3 is a diagram showing the voltage-current characteristics of the semiconductor laser device of the present invention, and FIG. 4 is a diagram showing the present invention. FIG. 5 is a sectional view of another embodiment of the invention. FIG. 5 is a diagram showing a response waveform of the embodiment of the invention. FIG. 6 is a sectional view of still another embodiment of the invention in the resonator direction. 1...p-1nP substrate, 2...p-nP buffer layer, 3-...n-1nGaAsP active layer, 4...n-
1nP cladding layer, 5...high resistance region, 6...p-1nP layer, 7...n-1nP layer, 8...p10 region, 9...5i07 film, 10...n Alliance electrode, 11...p alliance electrode. 12...p-type electrode. 13.-p-InGaAsP layer, 14... Diffraction grating. Patent applicant Nippon Telegraph and Telephone Corporation Representative Patent attorney Yoshi Tani - 1st
Figure 2 Voltage [Power Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1) A pnpn multilayer structure consisting of at least three grown layers on a p-type semiconductor substrate, the substrate, an uppermost n-type layer, and a pnpn layer immediately below the uppermost n-type layer. 1. A semiconductor laser device, wherein each of the type layers is provided with an electrode, and either one of the n-type and p-type growth layers interposed in the junction is an active region. 2) The pnpn multilayer structure is a multilayer structure consisting of a p-type buffer layer, an n-type active layer, an n-type cladding layer, a p-type layer, and an n-type layer. Semiconductor laser equipment. 3) The semiconductor laser device according to claims 1 and 2, wherein the compositional wavelength of the p-type layer is longer than the compositional wavelength of the n-type active layer. 4) The semiconductor laser device according to any one of claims 1 to 3, wherein the substrate or the growth layer has a second-order diffraction grating. 5) The semiconductor laser device according to any one of claims 1 to 4, wherein the active region has a band shape with both sides sandwiched between high-resistance semiconductor regions.