JPS59218749A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable to utilize for an electric isolation or an optical isolation by emitting a laser light having dosage of the degree which is equal to or shorter than the absorption end wavelength of a compound semiconductor in the wavelength and does not anneal the surface. CONSTITUTION:A P-N junction 2 is formed, for example, in the vicinity of the surface of a GaP crystalline substrate 1, a photoresist film 3 is covered on the surface of the substrate 1, and holes 4,... of the desired pattern are formed thereat. A pulse laser light 5 of 440nm of wavelength having, for example, 0.6mum of pulse width is emitted to the surface of the substrate 1 through the holes 4, and segregated layers 6,... of phosphorus are formed in the vicinity of the surface of the substrate 1 at this time. Such segregated layers of the P are near insulator and near black in color, the junction 2 is electrically isolated by the layers, and a light generated near the P-N junction is isolated.

Description

[Detailed Description of the Invention] (A) Industrial Field of Application The present invention is applicable to electrical element isolation in the production of ICs using compound semiconductors or optical isolation technology in the production of electronic technology. Application is possible.

(U) Prior Art Recently, there has been a growing trend to utilize laser light as a process technology for manufacturing semiconductor technology. That is, in 81 semiconductors, ion implantation is used to fabricate IC+LSI, but the purpose is to activate the impurities implanted by the ion implantation method, and to anneal the damaged layer that occurs during implantation to improve crystallinity. It is used for the purpose of recovery, for the purpose of recovering physically or chemically generated surface defects, or for the purpose of crystallizing amorphous formed on the semiconductor surface by laser annealing. Attempts are underway to utilize laser light. These methods mainly utilize the thermal energy of laser light to produce an annealing effect, with the aim of producing semiconductor surfaces that can be used in devices.

Recently, however, attempts have been made not only to utilize the annealing effect of laser light, but also to actively utilize special phenomena caused by laser light irradiation.

For example, a semiconductor surface is irradiated with a laser beam with an energy (wavelength) corresponding to the absorption edge energy of the semiconductor,
It has been discovered that the host material element is sputtered from the semiconductor surface irradiated with laser light even with a much smaller amount of Joule heat than the amount of Joule heat required to produce the annealing effect that occurs with normal irradiation. Attempts have been made to improve the detection of elements on the semiconductor surface and to form a mixed crystal layer near the hederojunction. As described above, by irradiating semiconductors with laser light, new phenomena that were previously unimaginable have been discovered, and devices that utilize these phenomena are being manufactured.

(c) Purpose of the invention The present invention is based on the discovery of a new phenomenon caused by laser beam irradiation.
This invention involves the invention of a new device manufacturing technique that utilizes this phenomenon, and is intended to be used for electrical element isolation in IC manufacturing and for isolating light to optoelectronic devices.

2) Structure of the Invention The method for manufacturing a semiconductor device according to the present invention is characterized in that the wavelength is equal to or shorter than the absorption edge wavelength of a compound semiconductor, and the radiation dose is such that the semiconductor surface is not annealed. By irradiating the surface of the semiconductor, a segregation layer composed of 1'), an element that becomes the N material of the semiconductor, is formed near the surface of the semiconductor.

The novel phenomenon that forms the basis of the present invention will now be explained.

Figure 1 shows that when a GaP (potassium phosphide) surface is irradiated with pulsed laser light, the segregation layer formed on the GaP surface due to the difference in the /ζ las width of the laser light is investigated using the backscattering method. It is something that As for the pulsed laser beam irradiation method, the laser beam wavelength is 440n in the figure (a).
m, the pulse width is 0.6 s, and in the same figure (b), the laser beam wavelength is the same but the pulse width is changed to 15 ns.

Assuming that the total heat amount in laser beam irradiation is 1.8 J cm-'', the peak value, or peak power, is changed to change the pulse width.If you think about it simply, it is 0.6 μS and 15 ns.
In the case of 15r1g, the beak power is about 40 times larger than that of 0.6 μs.

Under these conditions, the difference in the solid surface before and after irradiating the GaP surface with laser light was investigated using the Hanks scattering method. The random spectrum and aligned vector are shown, and the white and black circles represent the random spectrum and channeling spectrum after irradiation. First, if we pay attention to the Kumu/Kum spectrum, in the random spectrum before irradiation, the position of the Ga spectrum caused by -C loss scattering by the Ga element (J is approximately 1.2 MeV, and the P spectrum caused by scattering by the P element The position of is approximately 1.05 MeV, but after laser irradiation, the position of the Ga spectrum shifts to the low-energy Keyey law, whereas the position of the P spectrum remains unchanged.Ga spectrum, P spectrum In both cases, a peak is seen near the GaP surface compared to before irradiation.From these results, an excessive P layer is formed near the very surface of the GaP surface due to laser light irradiation, and further below - ( It can be seen that an excessive Ga layer is formed in No. 2. Looking at the - side channeling spectrum, the height of the channeling spectrum after laser beam irradiation is considerably higher than before irradiation. G
The excessive filtration layer and the excessive Ga layer formed on the aP surface layer are damaged by laser light irradiation, indicating that their crystallinity is disturbed.

On the other hand, in the case of laser beam irradiation with a pulse width of 15 ns in FIG. 1(b), no change is observed in the random spectrum between before irradiation (solid line) and after irradiation (white circles). The channeling spectrum is slightly higher after irradiation (black circle) than before irradiation (dashed line). This indicates that the crystallinity has not been fully recovered even though it has been slightly damaged by laser light irradiation. However, it is clear that the crystal is annealed compared to the 0.6 μs pulsed laser beam j (θ radiation).When irradiating laser beams in this way, the solid surface is When the irradiation needle is damaged by irradiation, annealing occurs and crystallinity is restored at the same time, but when irradiated with a laser beam with a small peak power and a relatively large pulse width, segregation of host material elements occurs on the solid surface. In ■-■ compound semiconductors such as Gap, GaAs (gallium arsenide), and Ink (indium phosphide), the laser irradiation dose to cause the above segregation is 09 to 2, OJcm-'' or an appropriate amount. The wavelength is equal to the absorption edge wavelength of the compound semiconductor)
, it must be shorter than that, so that the Rede light can pass through the semiconductor without being absorbed.

(P) Embodiment FIGS. 2 to 4 show an embodiment in which electrical and optical separation is achieved using the present invention, step by step. In the process shown in Fig. 2, P N
The joint 2〉 is completed. This junction is necessary for a semiconductor device's function, such as a light emitting function, and its depth from the surface is several thousand to 1 μm. In the step shown in FIG. 3, a photoresist film (3) is deposited on the surface of the substrate (1), and openings (4) in a desired pattern are formed therein.In the step shown in FIG. 4 with a pulse width of 0.6 μs to the surface of the substrate (1) through the above opening (4>(4)).
A pulsed laser beam (5) with a wavelength of 40 nm is irradiated once,
At this time, near the surface of the substrate (1), segregation of P (phosphorus),
i#(6)(6)・ Can be done. This P segregation layer is close to an insulator and is close to black in color, so the segregation layer (
6), (6) electrically isolates the PN junction (2), and also isolates the light generated near the PN junction.

In the example L, the segregation layer (6) was used for both electrical isolation and optical isolation, or in some cases only one or the other was used.

(f) Effects of the Invention According to the present invention, electrical isolation and optical isolation in a semiconductor device can be performed to a high degree by laser irradiation.

[Brief explanation of the drawing]

Figure 1 is a curve diagram showing the laser irradiation effect, Figures 2 to 4
The figure is a group view of a manufacturing process showing an embodiment of the present invention. (1)・GaP crystal substrate, (6)・・Segregation layer. Figure 1 C) 9 1. Ot+ 12 energy
/ Mev ((1) 1.0 1112 energy/ tvleV (b)

Claims (1)

[Claims] (1) By irradiating the semiconductor surface with a laser beam whose wavelength is equal to or shorter than the absorption edge wavelength of the compound semiconductor and with a dose that does not anneal the semiconductor surface, A method for manufacturing a semiconductor device, characterized in that a segregation layer made of one of the elements serving as a material is formed near the surface of the semiconductor.