JPH07118472B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device in which a high-concentration semiconductor region is formed by ion-implanting impurities into a silicon substrate, and particularly, arsenic ion ion-implanted with phosphorus ions. The present invention also relates to a method for manufacturing a semiconductor device in which a junction having a depth of 1.0 to 2.0 μm is formed by using the above ion implantation.

[Conventional technology]

Conventionally, a high concentration of N is obtained by ion-implanting impurities.
In the manufacturing method of forming the type semiconductor region, phosphorus ions or arsenic ions are individually ion-implanted, high-temperature annealing at 1000 ° C. or higher is performed, and impurities are activated and impurities are pushed.

[Problems to be solved by the invention]

 The conventional manufacturing method described above has the following drawbacks.

(1) When a high concentration N-type semiconductor region is formed by implanting phosphorus ions, in order to remove crystal defects caused by phosphorus ion implantation, after performing phosphorus ion implantation through a thin oxide film, 700 to 1000 ° C. Annealing at the temperature of 106
It is necessary to perform heat treatment at a temperature of 0 ° C. or higher.

In this case, heat treatment at 1060 ° C. or higher is indispensable for recovery of crystal defects. Due to the heat treatment at 1060 ° C. or higher, the depth of bond that can be formed is 2.0 μm or more and a bond of 2.0 μm or less cannot be formed. .

(2) When arsenic ion is ion-implanted to form a high-concentration N-type semiconductor region, crystal defects caused by arsenic ion-implantation have a level that does not affect device characteristics by annealing at a temperature of 1000 ° C. or higher. To recover. However, in an ordinary integrated circuit having a P-type semiconductor region using boron on the same semiconductor substrate, there is a defect that the depth of a junction that can be formed is 1.0 μm or less due to the limitation of heat treatment.

An object of the present invention is to provide a method for manufacturing a semiconductor device which eliminates the drawbacks of the conventional method for manufacturing a semiconductor device, has good crystallinity, and can form a junction having a depth of 1.0 to 2.0 μm. It is in.

[Means for solving problems]

A feature of the present invention is that in a method of manufacturing a semiconductor device in which a high-concentration emitter region is formed by ion-implanting impurities into a base region, 3 × 10 ¹⁵ to Performing a step of implanting 1.5 × 10 ¹⁶ cells / cm ² of phosphorus ions, a step of implanting 3 × 10 ¹⁵ cells / cm ² or less of arsenic ions, and a low-temperature and low-concentration phosphorus diffusion at 700 to 900 ° C. Forming phosphorus glass, and then performing heat treatment at 900 ℃ ~ 1000 ℃ in a pure nitrogen atmosphere to stabilize the phosphorus glass, and then 0.5% pure nitrogen.
A step of heat-treating at a temperature of 950 ° C. or higher to push in arsenic impurities and phosphorus impurities in a gas atmosphere containing a trace amount of oxygen of up to 1.5%, and then a step of oxidizing in a steam atmosphere at a temperature of 800 to 950 ° C. And a junction between the emitter region and the base region is formed to a depth of 1.0 to 2.0 μm.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a bipolar transistor of a first embodiment formed by the manufacturing method of the present invention.

First, the N ⁺ type buried layer 2 is formed on the P type semiconductor substrate 1, and then the N type semiconductor region 3 that is a collector is epitaxially formed.
And then a P-type base region 5 is formed in the N-type semiconductor region 3 which is the collector of the bipolar transistor.
The oxide film 7 is provided, the oxide film in the portion where the emitter region 6 and the collector contact region 4 are to be formed is removed, a thin oxide film is provided, and 3 × 10 ¹⁵ to 1.
Phosphorus ions are ion-implanted at a dose of 5 × 10 ¹⁶ ions / cm ² , and then arsenic ions are implanted at a dose of 3 × 10 ¹⁵ ions / cm ² or less, so that the emitter region 6 and the collector contact region 4 are implanted. Formed at low temperature of 700-800 ℃ and 100ppm-1000pp
Phosphorus diffusion is performed by a gas containing a low concentration of phosphorus impurities of m to form a phosphorus glass layer 8 which is a passivation film. This heat treatment is performed at a temperature lower than the heat treatment temperature of the next step. After that, heat treatment is performed in a pure nitrogen atmosphere at a temperature of 900 to 1000 ° C. to stabilize the phosphorus glass layer, and then 0.5 to 1.5 is added to pure nitrogen at a temperature of 950 ° C. or higher.
Impurities are pushed in in a gas atmosphere containing a small amount of oxygen, and then oxidized in a steam atmosphere at a temperature of 800 ° C to 950 ° C.

By the above manufacturing method, it is possible to form an emitter region having a good crystallinity and a depth of 1.0 to 2.0 μm.

In other words, heat treatment at a temperature of 1060 ° C. or higher is necessary to form the emitter region in the ion implantation of only phosphorus ions and recover the crystal defects caused by the ion implantation. The depth of the junction between 5 and the emitter region 6 is 2.0 μm or more. By using the arsenic ion implantation together with the phosphorus ion implantation as in the present invention, compared with the case of only phosphorus ion implantation, The crystallinity can be recovered at a low temperature, and the junction between the emitter region 6 and the base region 5 of about 1.0 to 2.0 μm can be obtained.

The low temperature and low concentration phosphorus diffusion at 700 to 800 ° C. is performed simultaneously with the low temperature annealing after ion implantation and the step of forming a dense phosphorus glass layer acting as a passivation film. The process of heat treatment in a pure nitrogen atmosphere at a temperature of ℃ includes a high temperature annealing process in the two-step annealing method and a heat treatment process for stabilizing the phosphorus glass layer at the same time.

In addition, the gas atmosphere in the step of pushing impurities is 0.5% to pure nitrogen in order to improve the recovery of crystal defects.
A gas atmosphere containing a trace amount of oxygen of 1.5% is suitable.

FIG. 2 is a sectional view of a Zener diode of the second embodiment formed by the manufacturing method of the present invention.

First, as in the first embodiment, the N ⁺ type buried layer 2 and the N type semiconductor region 3 are formed on the P type semiconductor substrate 1, and then the high concentration P type semiconductor region 9 of the Zener diode is formed. After the oxide film 7 is provided and the oxide film in the portion where the high-concentration N-type semiconductor region 6 is to be formed is removed, the N-type semiconductor region 6 is combined with phosphorus ion implantation and elementary ion implantation as in the first embodiment. To form. In addition, 10 is an Al electrode.

This embodiment is effective when a shallow junction is required to control the Zener voltage.

〔The invention's effect〕

As described above, according to the present invention, by using the phosphorus ion ion implantation and the arsenic ion ion implantation in combination, the crystallinity of 1.0 to 2.0 μm, which cannot be formed by implanting phosphorus ion or arsenic ion alone, can be formed. There is an effect that it is possible to form a junction having a depth of.

[Brief description of drawings]

FIG. 1 is a sectional view of a bipolar transistor formed according to the first embodiment of the present invention, and FIG. 2 is a sectional view of a Zener diode formed according to the second embodiment of the present invention. 1 ... P-type semiconductor substrate, 2 ... N ⁺ type buried layer, 3 ... N
Type semiconductor region, 4 ... Collector contact region, 5 ...
Base region, 6 ... Emitter region (high-concentration N-type semiconductor region), 7 ... Oxide film, 8 ... Phosphor glass layer, 9 ... High-concentration P-type semiconductor region, 10 ... Al electrode.

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Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device in which a high-concentration emitter region is formed by ion-implanting impurities into a base region, and 3 × 10 ^{15 to} 1.5 are formed through a thin oxide film formed on a surface of a semiconductor substrate. × a step of 10 ¹⁶ Quai / cm ² phosphorus ion implantation, a step of ion-implanting arsenic ions 3 × 10 ¹⁵ Ke / cm ² or less, phosphorus performed phosphorus diffusion of low temperature and low concentration of 700 to 900 ° C. Forming glass and then heat treating at 900 ℃ ~ 1000 ℃ in pure nitrogen atmosphere to stabilize phosphorus glass, and then 0.5 ~ 1.5 in pure nitrogen.
%, A step of heat-treating at a temperature of 950 ° C. or higher to push in arsenic impurities and phosphorus impurities in a gas atmosphere containing a small amount of oxygen, and a step of oxidizing at a temperature of 800 to 950 ° C. in a steam atmosphere. A method of manufacturing a semiconductor device, wherein the junction between the emitter region and the base region is formed to a depth of 1.0 to 2.0 μm.