JPS59112617A - Laser annealing method for semiconductor device - Google Patents

Abstract

PURPOSE:To enable to realize preferable activation rate without damaging a semiconductor to become a semiconductor substrate by implanting a substance having long basic absorption wavelength as compared with the substrate in addition to an ion implantation into a region surface layer of part of the substrate. CONSTITUTION:Si ions are implanted to a substrate formed of a semi-insulating GaAs to form an Si ion implanted layer 2. Then, Te ions are, for example, implanted as a substance to become a heat generating medium by an ion implantation method to form a Te-ion implanted layer 3. Thereafter, an annealing is executed by a laser. Since the passing ranges of the GaAs and the Si are respectively 10-15mum and 1.2-15mum and the passing range of the Te is 3.5- 8.0mum, the wavelength of the laser to be used is selected to the range of 1.5- 3.5mum. In the process, the GaAs and the Si do not almost absorb light, but only the Te absorbs the light to generate heat. The Si substitutes for the position of the Ga in the GaAs crystal by this heat energy and is activated as N type impurity.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to the use of an ion implantation method to inject impurities into the region of a half- and seven-body device. In order to activate the laser annealing method,
Do two.

(2) 4F behind the technology The ion implantation method is much easier to control the depth and size of the impurity introduced than the diffusion method. 1), it is essential as a means to introduce impurities into semiconductors.

Incidentally, even in this ion implantation method, an annealing step is essential for activating the impurity introduced into the semiconductor. There are two types of annealing methods: an annealing method that uses normal force and heat treatment, and a laser annealing method that uses thermal energy generated by laser radiation.The former requires heating the entire substrate, but the latter By selective irradiation in the geometrical sense of the laser, impurities () are
It is possible to activate only the ionized region, and it can be said that this method is particularly suitable for activating the above-mentioned ion-implanted first substance.

The present invention is an improvement on the laser annealing method used to activate the ion-implanted material 5r.

(3) Conventional technology and problems In the conventional technology, this laser annealing method is
[4] After ion implantation, the second step is performed by irradiating the ion with a laser having a wavelength shorter than the fundamental absorption edge wavelength inherent to the implanted material. At this time, the impurity absorbs the irradiated light, generates thermal energy, and is activated.

However, the half N1. Depending on the body, the fundamental absorption edge wavelength is close to the fundamental absorption edge wavelength of this impurity.In this case, it is natural to use a laser beam with a wavelength selected to activate the impurity. However, it is absorbed by the semiconductor that forms the substrate, and due to the thermal energy generated thereby, it is generally annealed;
7. If the number is too high, the board will suffer from damage such as thermal transformation or other disadvantages. In order to solve this problem, it is conceivable to shift the wavelength of the laser to a slightly longer wavelength, but even if the original scratches on the substrate are maintained, the implanted impurities will not be affected. This often results in the inability to obtain the desired activation rate.

In other words, the rise of the extinction coefficient near the fundamental absorption edge wavelength, especially on the tJA wavelength side, is extremely steep, so it is good to interpret this wavelength appropriately! The drawback is that it is extremely difficult to use and is not easy to control.

A specific example is the case where silicon ions (Si") are implanted as n-type impurities into a substrate made of gallium arsenide (GaAs). The fundamental absorption edge wavelength of silicon (Sl) is 1.2 [μm]. ] In contrast, the diameter of gallium arsenide (GaAs) is about 10 [μm], which is very close to that of silicon (Sl). Therefore, in order to activate silicon (Sl), wavelength 10 [μ
When irradiated with a laser beam of about 100 m], the substrate gallium arsenide (GaAθ) absorbs the light and generates heat, causing Ji4-Il! J
You will receive the following.

(4) Purpose of the invention The purpose of the present invention is to eliminate this drawback.
In the laser annealing method, which is used to activate impurities deposited in a partial region of a half-f-body device by ion implantation, it is possible to damage the semiconductor that serves as the substrate. It is an object of the present invention to provide a laser annealing method for a semiconductor device that can achieve a high conversion rate of 1.

(5) Structure of the Invention The above object is to (a) provide a laser annealing method for activating impurities ion-implanted into a part of a semiconductor device in a trance region of a semiconductor device; This is achieved by introducing a substance with a longer basic absorption edge wavelength into the surface layer of the partial region, and then irradiating the laser beam with a wavelength that is absorbed by the proboscis but not absorbed by the semiconductor. .

In addition, in the configuration of (a) above, (b) prior to the material having a long absorption edge wavelength, protection is provided in some areas of the material with a long absorption edge wavelength. or (
c) It is more effective if the method of converting the substance fj1 having a long basic absorption edge wavelength is an ion implantation method.

Furthermore, in (2) the above-mentioned shaving a), (b) and (c), the laser irradiation may be performed while heating the tl'J-kihan-1 body, and (e) the above-mentioned 4? In configurations (a), (b), (c), and (b), the laser beam may be emitted intermittently.

The inventor of the present invention did not directly activate the ion-implanted By introducing this into the semiconductor, this a:,7 no'
We came up with the idea that the above drawbacks could be overcome by indirectly activating the implanted impurity using the thermal energy generated by 71-1 absorbing the laser beam.

Therefore, the inventor of the present invention created a light transmission region (Transmissi○n reg
Taking advantage of the fact that Tanimotora is almost transparent to light in this region, after ion-implanting the desired impurity, the # conductor that becomes the substrate also has the basic absorption 'IY ym wavelength. By using ion implantation, etc., we introduce a substance that becomes a heat generating medium for a long period of time, so that it is absorbed by some substances but not by semiconductors. By irradiating a laser beam with a certain wavelength, the semiconductor substrate does not generate heat, and only the physical chain θ The present invention was completed after experimentally confirming that a high conversion rate could be obtained.

Figure 1 shows the transmission area of the divine materials in wavelength units. In the diagram, to the left of winter p! The number shown in the figure is the basic absorption edge wavelength of the material), and the region up to the wavelength shown on the right side is the transmission region.

For example, in the case of gallium arsenide (GaAs) and silicon (Si) mentioned above, each transmission area is 10 to 15 [μl
11), 1.2 to 15 [μm], and is seven [dl
-, it is clear that direct laser annealing is similar and difficult. However, if some tellurium (Te) is introduced as a heat generating medium in a 4i% region of 35 to 8.0 [μm] and irradiated with a laser with a wavelength in the range of 1.5 to 35 [μm], this The wavelength is gallium arsenide (Ga
As), silicon (Si) i2 and di3h%
e, since it is an internal region, there is almost no absorption by these two, and absorption occurs only in tellurium (Te) (), and the thermal energy generated based on this is used to activate the target silicon (Si). happen.

In the above process, prior to introducing the substance that becomes the heat generating medium, aluminum nitride (A/N), silicon dioxide (8102), and silicon oxide (S: 13N4) are added to a part of the extension area of the Z position of the *14'fi body. Form a protective film i) such as 7°
In the case of type impurities, it is possible to control up to .41 and 0, which is lower than in the above process, while in the case of p-type impurities, only this method can be used.

In addition, it is desirable to obtain the target wavelength of the laser in advance using a filter, etc., and the laser irradiation is performed at a low temperature of 30°C to the extent that the composition of the semiconductor substrate is not aggravated.
It may be carried out while heating with a gamma blackness of 0 to 400°C, and further, it may be carried out using a pulsed laser to give a temperature of 7 degrees Celsius.

(6) Embodiments of the Invention With reference to the following, a practical example C of the present invention - a laser annealing method for a semiconductor device will be explained, and the unique effects of the present invention will be clarified.

In one example of forming an n-type layer by implanting silicon ions (Si) into a semi-insulating gallium arsenide (GaAs) substrate, (a) no protective film is formed on the substrate. A case in which laser annealing is performed first, and a case in which (b) a corneal preservation layer is formed on the substrate and then laser annealing is performed will be described.

(a) When laser annealing is performed without forming a protective film on the substrate, see Figure 2. Silicon ions (611 + ), and a silicon ion (Si+) implanted layer 2 is formed to a depth of about 800 to 1.2 oo (M). In this process, the injection amount is 90 (Ke
The VJ level, dose, and hio were approximately 1.012C (1.012C). ), and the tellurium ion (Te") implanted layer 3 is formed into a type I. In this process, the implantation energy is 180 (K e V
]'43, the dose was about IQ16 (cm, -2:). Then, for example, YAG (Yttriu
mAluminumGarnet) laser for IjQ [2 and annealing is performed. Gallium arsenide (C)aAs)
, the silicon (Sl) trench area is 10 to 15 [
[μm], 1.2 to 15 [μm], whereas the range of tellurium (Te) is 35 to 80 [μm],
The γ length of the laser used must be selected in the range of 15 to 35 [μm]. In this process, gallium arsenide (GaAs) and silicon (Si) hardly absorb light, and only tellurium (Te) absorbs light and generates heat, and this thermal energy causes silicon (Sl) to transform into gallium arsenide (GaAs). Gallium (Ga) is located at fj fip in the crystal and is activated as an n-type impurity.

(b) When a protective film is formed on the substrate and then laser annealing is performed, the substrate 11-
Next, a sputter growth method was used to produce aluminum (A).
eN) from rc jl, i! Forms a holding g (9il-%H2) with a u of 500 (X) od degrees.

Using the ion implantation method shown in FIG. 5, silicon ions (Si+) are introduced into the base plate 11 through the protective film 21 to form a silicon ion (Si+) implanted layer 12.

FIG. 6 Tellurium (Te) is deposited on the internal illuminant film 21 using a vacuum evaporation method.
113 is formed at a spacing of about 1500 [s], and annealing is performed by irradiating the selected laser from the front or back surface of the substrate in the same manner as in the case (a) above.

After annealing, protective film 12 and tellurium (Te) layer 13
is removed using a wet etching method using hydrofluoric acid (HF), hot phosphoric acid (H3PO4), etc. once a month.6 According to this process, compared to the method (a) above, Thus, it is possible to form an n Lurie region with low Q l& with good controllability.

Furthermore, when forming a p-type region, only method (b) can be used.
This can be done by using 4.

In addition, the semiconductor that becomes the substrate, 1+:j, for example, Noricon (S
l), Germanium (Ge), Gallium Hi% (()a
As), indium phosphide (InP), etc., and the substance a that becomes the heat generating medium, the key point is to combine the material a to be used as a heating medium. It goes without saying that the effect of one beam can be obtained.Also, gas lasers, solid-state lasers, # field lasers, etc. can be used as lasers for irradiation, but before irradiation, It is desirable to obtain an appropriate wavelength using a filter or the like.

Furthermore, if the number of sets of semiconductor substrates changes when the conductor is heated to a low temperature of 300 to 40 degrees (1'oC) and then laser irradiated, it becomes active. This is very effective in improving the TP ratio, and flash heating may also be performed using a pulsed laser.

(7) As for the detailed description of the invention, according to the present invention, the semiconductor 91'''
Part of 1'i usubo 1 niionn master law (2yo0),・α
People 11. In the laser annealing method that reduces impure impurities to 2 ↑ 1 (: turned into ta N), without damaging the semiconductor that serves as the substrate], can we realize a favorable activation force and create a semiconductor that can be used? '74 laser annealing method can be provided.

4 The f + j'i simple Ryoming figure 1 of the same song is a diagram showing the glazed object T ■ sledding disaster area 0,
FIGS. 2 and 3 are 1) iT surface views of the substrate after completion of each green hardening process in the laser annealing method performed without using a protective layer according to the first embodiment of the present invention. , 4th
6 to 6 are cross-sectional views of the substrate after completion of each main annealing process in a laser annealing method using a supine film, which is a second embodiment of the present invention.

1, H-・Substrate (semi-insulating GaAθ), 2, +2-=
Silicon ion (S j, ”) implantation f8 castle, 3...tellurium ion (Te+) implantation region, 13... tellurium (T
e) Layer, 21...Poem fl"j (A e N)r
s Agent Patent Attorney Hiroshi Matsuoka 4th Division'
-:- No. 30 7 to Nishiki 4

Claims (5)

[Claims] (1) In a laser annealing method for activating impurities ion-implanted into a partial region of a semiconductor device, in addition to the ion implantation, a substance with a fundamental absorption edge wavelength longer than that of the semiconductor is introduced into the surface layer of the partial axial region. 1. A method for laser annealing a semiconductor device, the method comprising: irradiating a laser with a wavelength that is absorbed by the substance but not absorbed by the semiconductor. (2) 1 (including the step of forming a protection film in the partial plateau prior to the introduction of the substance with a long fundamental absorption edge wavelength η゛h);
``Laser annealing method for semiconductor device 11q'' (3) The method for preparing the substance with a long basic absorption edge wavelength is ion implantation.Claim 1 J, A 41
11! Laser annealing method for 11" semiconductor device. (4) Claim 1, 2, or 3E, wherein the laser irradiation is performed while heating the semiconductor device.
Laser annealing method for semiconductor device 1'a. (5) The laser irradiation is performed intermittently;
A laser annealing method for a semiconductor device 1't according to the range 1f, 7q, 2nd term, 3rd term, or 4th term Mo1:.