JPS62291164A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the leakage current of a semiconductor device by ion implanting twice a reverse conductivity type impurity to a substrate to an emitter region in a base region and a cathode region in an anode region by altering the conditions of a high acceleration voltage and a low acceleration voltage. CONSTITUTION:Reverse conductivity type impurity to a substrate 10 is implanted twice to emitter regions 21, 22 in a transistor base region 20 and cathode regions 31, 32 in an anode region 30 by altering the conditions of high and low accelcration voltages. Then, it is heat treated to form the junction of the cathode regions shallower than that of the emitter regions and at high density. Since the ion implantations are divided into two in this manner and the second implantation is to near the surface by avoiding the first deep implantation, a crystal defect is suppressed as compared with a conventional method for ion implanting a large quantity of ions, resulting in a decrease in the current leakage of a constant-voltage diode.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and in particular, to a method of manufacturing a semiconductor device, in particular, the emitter of a transistor of a bipolar integrated circuit and the cathode of a constant voltage diode are formed by ion implantation. The present invention relates to a method for manufacturing semiconductor devices that are simultaneously formed.

[Conventional technology]

Conventionally, emitter formation of transistors in bipolar integrated circuits has been mainly performed by gas diffusion. Recently, as wafers have become larger in diameter, ion implantation methods with less in-plane variation have come into use.

When an integrated circuit includes a constant voltage diode, ions are implanted onto an anode region having a higher impurity concentration than the base region of the transistor at the same time as emitter vines are formed to form a cathode region.

[Problem that the invention seeks to solve]

However, in the conventional manufacturing method described above, ions are implanted once and at a high concentration, which induces crystal defects near the surface. For this reason, a constant voltage diode that uses a junction near the surface that is shallower than a transistor has the disadvantage of causing current leakage. One way to eliminate crystal defects is to reduce the amount of ion implantation, but this is not a solution because the reduction in the amount of impurities causes a decrease in the hPE of the transistor and an increase in the voltage of the constant voltage diode. In the end, it was impossible to implement ion implantation into integrated circuits containing constant voltage diodes.

An object of the present invention is to provide a method for manufacturing a semiconductor device having a helangistor and a constant voltage diode, in which the cathode region of the constant voltage diode is formed to be shallower and more concentrated than the emitter region of the transistor, which causes an increase in the voltage of the constant voltage diode. It is an object of the present invention to provide a method for manufacturing a semiconductor device in which a cathode and an emitter region are formed by ion implantation, which does not cause leakage current, and does not cause a decrease in hFE of a transistor.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes forming two regions in a semiconductor substrate that are of the same conductivity type as the substrate and have different surface impurity concentrations, and a region with an internal concentration of the formed regions is used as a base region of a transistor and a high concentration region. In a method of manufacturing a semiconductor device in which a concentration region is an anode region of a constant voltage diode,
a step of ion-implanting an impurity of a conductivity type opposite to that of the substrate into the emitter region in the base region and the cathode region in the anode region in two steps under different conditions of high acceleration voltage and low acceleration voltage; and a step of heat treatment, and the junction in the cathode region is formed to be shallower and more highly concentrated than the junction in the emitter region.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a semiconductor device formed according to an embodiment of the present invention. In FIG. 1, collector contact regions 23, 24 and base regions 20 are included in the vapor growth layer 10.
．． An NPN) radiator consisting of emitter regions 21° and 22 is formed. On the other hand, the voltage regulator diode has an insulated anode,
31 and 32 are formed as cathodes. Figure 2 (
a> and (b) are shown in order of steps to explain one embodiment of the present invention. FIG. 1 is an enlarged sectional view of the broken line portion in FIG. 1;

In Fig. 2 <a), the acceleration voltage is 50 eV ~ 150 feV,
Phosphorus is implanted at a high acceleration energy and a high dose of 5X101S to 2X10'6 to form an N+ region 2131. At this time, since the base region 20 and the anode region 30 have different impurity concentrations, the first ion-implanted emitter region is formed deeper than the first ion-implanted card region. Subsequently, ion implantation is performed by changing the implantation conditions. That is, the accelerating voltage was lowered to 40 eV, and the dose was also reduced to 2X1.
0'5 or less to form a region 22°32 as shown in FIG. 2(b). Since the accelerating voltage is low in the regions 22 and 23, the maximum impurity concentration is near the surface. After that, it is heat treated and pressed to a predetermined depth to complete it.

In the above embodiments, ions were implanted at a high accelerating voltage for the first time and at a low accelerating voltage for the second time, but it goes without saying that the object of the present invention can be achieved even if this is reversed.

〔Effect of the invention〕

As explained above, in the present invention, ion implantation is divided into two steps, and the second ion implantation is implanted close to the surface to avoid the depth of the first ion implantation, so a large amount of ions are implanted at one time. Compared to conventional methods, crystal defects are suppressed,
As a result, current leakage from the constant voltage diode is reduced.

Further, due to the heat treatment after the ion implantation, the impurities from the first ion implantation are also diffused in one direction, and are added to the impurities from the second ion implantation to form a constant voltage diode region. Therefore, the impurity concentration necessary to obtain a predetermined constant voltage can be obtained.

On the other hand, the emitter region of the transistor is deeply implanted.
The total amount of impurities from the first ion implantation and the second ion implantation becomes the emitter concentration, and the desired hPR can be obtained.

Regarding the increase in the number of steps, ion implantation increases by one time, but
Ion implantation with good concentration control has the great advantage of reducing variation in characteristics, resulting in an overall improvement.

61

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a semiconductor device formed according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are diagrams of FIG. It is an enlarged sectional view of the broken line part. 10... Semiconductor sales, 11... Insulating film, 20...
Transistor base region, 21..First ion implantation emitter region, 22..Second ion implantation emitter region, 23.
...First ion implantation collector contact region, 24...
Second ion implantation collector contact region, 30... Constant voltage diode anode region, 31... First ion implantation collector contact I- region, 31. First ion implantation cathode region, 32... Second ion implantation cathode region. Flower 2 field

Claims (1)

[Claims] Two regions of the same conductivity type as the substrate but with different surface impurity concentrations are formed in the semiconductor substrate, and of the formed regions, the low concentration region is used as a base region of a transistor, and the high concentration region is used as an anode region of a constant voltage diode. In the method for manufacturing a semiconductor device, an impurity having a conductivity type opposite to that of the substrate is added to an emitter region in the base region and a cathode region in the anode region under different conditions of high acceleration voltage and low acceleration voltage. Manufacturing a semiconductor device, comprising a step of ion implantation in two steps and a step of subsequent heat treatment, and forming a junction in the cathode region to be shallower and more concentrated than a junction in the emitter region. Method.