JPS6285427A - Heat treating method for semiconductor device - Google Patents

Abstract

PURPOSE:To highly integrate or accelerate one layer in a semiconductor device by implanting impurity ions to a semiconductor substrate, then emitting a microwave to activate it, thereby suppressing the spread of the impurity implanted region. CONSTITUTION:Impurity ions are implanted to a semiconductor substrate, and a microwave is then emitted to activate it. The region which becomes amorphous by implanting impurity ions such as arsenic ions or P ions to the substrate more readily absorbs the microwave of, for example, 2.45 (GHz) then the portion which is not amorphous. Accordingly, if the impurity ions are implanted by an ion implanting method and the microwave is emitted when forming a necessary impurity region in a semiconductor device, the region to which the impurity ions are implanted mainly absorbs the microwave to be heated. Thus, thermal influence is hardly affected to the semiconductor portion to which the ions are not implanted or a wiring portion which reflects the microwave but impurity atoms can be activated.

Description

[Detailed Description of the Invention] [Summary] The present invention is a heat treatment method for a semiconductor device in which a semiconductor substrate (or semiconductor layer) into which impurity ions are implanted is irradiated with microwaves to mainly generate heat in an impurity-introduced region. ,
By making it possible to electrically activate impurity atoms without adversely affecting other parts, the expansion of the impurity-introduced region can be suppressed and the integration of semiconductor devices can be further increased. Enables high speed.

[Industrial application field]

The present invention relates to a heat treatment method for a semiconductor device that can be applied to electrically activate implanted impurity atoms and achieve good results.

[Conventional technology]

Currently, when manufacturing semiconductor devices, it is common practice to apply ion implantation to form impurity introduced regions.
It has become an essential technology.

When forming an impurity-introduced region using the ion implantation method, it is absolutely necessary to implant impurity ions into the semiconductor substrate (or semiconductor layer) and then perform heat treatment to electrically activate the impurity atoms.

Usually, such heat treatment is carried out by a closed tube method, that is, by inserting the semiconductor wafer into a quartz tube and heating the quartz tube in an electric furnace. Measures such as heating by irradiating light have also been adopted.

[Problem that the invention seeks to solve]

Among the conventional heat treatment methods, means using an electric furnace include:
Quite high temperature, for example about 900℃ to 1000℃
C), the entire semiconductor wafer is heated, and the impurity-introduced region is therefore enlarged.

FIG. 2 shows a diagram for explaining the carrier felt degree distribution when heat treatment is performed using an electric furnace.

In the figure, the horizontal axis represents the depth from the semiconductor wafer surface, and the vertical axis represents the carrier concentration.

In the figure, ■ is 1.88 (, 1°L) immediately after ion implantation.
indhard M, 5-charf f H,F
,.

Σchiott) represents a theoretical curve, and ■ represents a carrier distribution curve obtained experimentally.

The ion implantation and heat treatment conditions under which this data was obtained are as follows.

Semiconductor substrate: p-type silicon (Si) Impurity ions: 1g (p) Dose I: 5 x 10+5 (cm-”) Implantation energy: 80 (KeV) Heat treatment temperature = 900 [°C] Heat treatment time: 30 [minutes] From the figure As is clear, the distribution curve (2) according to the prior art is approximately twice as large as the theoretical distribution curve (G,') in the depth direction.

Furthermore, when using a means for irradiating light from a laser or a lamp, the heat treatment time is shorter than when using the electric furnace.
There is no big difference in that the ambient temperature needs to be kept at Tm.

Nowadays, there is still a strong demand for higher integration in semiconductor devices, and therefore, further improvements are needed not only in terms of microfabrication, but also in shallowly forming impurity-introduced regions and, related to this, in lowering the process temperature. Advanced technology is required.

The present invention enables heat treatment for activating impurity atoms to be performed at a low temperature when forming an impurity-introduced region by applying an ion implantation method, thereby preventing the impurity-introduced region from expanding. The aim is to achieve higher integration or higher speed of semiconductor devices.

[Means for solving problems]

As a result of numerous experiments, the present inventors discovered that impurity ions, such as arsenic (As), were added to the semiconductor substrate (or semiconductor layer).
) A region that has been made amorphous by implanting ions or P ions, etc., has a 2. 45 (Gllz) was found to easily absorb microwaves.

Therefore, when forming impurity regions necessary for semiconductor devices,
When impurity ions are implanted using the ion implantation method and microwaves are irradiated, the region into which the impurity ions are implanted mainly absorbs the microwaves and generates heat, so it Activation of impurity atoms can be achieved with almost no effect of heat on parts that do not require heat treatment, such as parts of wiring that reflect waves.

Therefore, in the present invention, impurity ions are implanted into a semiconductor substrate (or a semiconductor layer) and then microwaves are irradiated to activate the impurity ions.

[Effect]

In the above manner, only the region into which impurity ions are implanted generates a large amount of heat, and the other regions are hardly affected by the heat. It is possible to activate atoms, and it can contribute to higher integration and higher speed of semiconductor devices.

〔Example〕

FIG. 1 shows a diagram for explaining the carrier concentration distribution obtained by implementing the present invention.

In the figure, the horizontal axis represents the depth from the semiconductor wafer surface, and the vertical axis represents the carrier concentration.

In the figure, ■ is the LS immediately after ion implantation as in Figure 2.
The S-theoretical curve and ■ indicate the carrier distribution curve according to an embodiment of the present invention, respectively.

The ion implantation and heat treatment conditions under which this data was obtained are as follows.

Semiconductor substrate: p-type Si Impurity ion: P Dose amount: 5 X I Q15 (am-”) Implantation energy: 80 (KeV) Microwave frequency: 2.45 (Gllz) Microwave electric crab 600 (W) Figure As is clear from the above, it can be seen that the distribution curve (■) according to the present invention almost coincides with the theoretical distribution curve,
Therefore, it is possible to form an extremely shallow impurity-introduced region.

〔Effect of the invention〕

According to the heat treatment method for semiconductor devices according to the present invention, impurity ions are implanted into a semiconductor substrate (or a semiconductor layer) and then activated by irradiation with microwaves.

In this way, the area into which impurity ions are implanted has a high absorption rate of microwaves, so the heat generation there is significantly larger than in the other five page areas, and therefore the impurity-introduced area expands. Since it is possible to easily obtain a shallow junction by activating impurity atoms without any interference, it is effective for increasing the integration and speed of semiconductor devices.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the carrier concentration distribution when heat treatment is performed according to an embodiment of the present invention, and FIG. 2 is a diagram showing the carrier concentration distribution when heat treatment is performed according to the conventional technique. Each diagram represents a diagram for explanation. In the figure, ■ is the theoretical curve of r,ss immediately after ion implantation, ■ is the carrier distribution curve when using the conventional technology, and ■
1 and 2 respectively show carrier distribution curves according to an embodiment of the present invention.

Claims (1)

[Claims] 1. A heat treatment method for a semiconductor device, which comprises implanting impurity ions into a semiconductor substrate (or a semiconductor layer) and irradiating them with microwaves to activate them.