JPH0527993B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor integrated circuit device, and more particularly to a semiconductor integrated circuit device including a Schottky diode.

(Prior Art) One type of semiconductor integrated circuit device includes a Schottky diode.

FIG. 4 is a configuration explanatory diagram showing an example of such a conventional semiconductor integrated circuit device. In FIG. 4, reference numeral 1 denotes a p-type semiconductor substrate, on which an n ⁺ type buried region 2 is selectively formed near its surface, and an n-type epitaxial layer is formed to cover this buried region 2. A coating layer 3 is formed. An n ⁺ type collector region 4, a p type insulating isolation region 5, and a type base region 6 are formed in the epitaxial layer 3;
An n ⁺ type emitter region 7 is formed in the base region 6 . Reference numeral 8 denotes an oxide film formed to cover the surface of the epitaxial layer 3 and each of these regions 4 to 7, and this oxide film 8 is selectively removed to cover the epitaxial layer 3 and each of these regions 4 to 7. Electrode contact portions 31, 41, 61 and 71 are formed. 10 is an electrode contact part 31,
41, 61, and 71 are platinum silicides selectively formed; 11 is a barrier metal such as Ti-W that is selectively formed to cover the surfaces of these platinum silicides 10; 12 is a barrier metal that covers the surface of the barrier metal 11; This is a wiring member made of aluminum or the like that is selectively formed.

With this configuration, a Schottky junction is formed in the electrode contact portion 31, and an ohmic junction is formed in the electrode contact portions 41, 61, and 71, so that an ohmic junction is formed between the base and collector of the npn transistor. A bipolar semiconductor integrated circuit device in which the Schottky diode is clamped is obtained. Here, the platinum silicide 10 and the barrier metal 11 suppress the reaction between the epitaxial layer 3 and the wiring member 12, thereby realizing a semiconductor integrated circuit device having a Schottky diode with high quality and stable characteristics. be able to.

(Problems to be Solved by the Invention) However, according to such a conventional configuration, platinum silicide and barrier metal must be provided, and equipment and processes for providing these are required, resulting in high costs. It gets expensive.

The present invention solves these conventional drawbacks, and its purpose is to provide a semiconductor integrated circuit device having a Schottky diode of high quality and stable characteristics with a relatively simple configuration and at low cost. It is about realization.

(Means for Solving the Problems) The present invention, which solves these problems, provides a semiconductor integrated circuit device including a Schottky diode, in which silicon containing a small amount of nitrogen is placed under the electrode of the Schottky diode. It is characterized by the formation of layers.

(Example) Hereinafter, it will be explained in detail using the drawings.

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention, and the same parts as in FIG. 4 are given the same reference numerals. In FIG. 1, 13 is an oxide film 8;
a silicon nitride film containing more silicon than nitrogen (this is called silicon-rich), which is formed so as to cover the entire surface of each electrode contact portion 31, 41, 61, and 71 formed by selectively removing 14 is a silicon layer containing a trace amount of nitrogen.

The silicon nitride film 13 can be formed, for example, by heat treatment in an atmosphere containing a mixture of ammonia (NH ₀ ) and silane (SiH ₄ ). A silicon layer 14 containing a small amount of nitrogen is formed on 61 and 71. After forming the silicon nitride film 13 in this way, the silicon nitride film 13 formed on the silicon layer 14 containing a trace amount of nitrogen in the electrode contact portions 31, 41, 61 and 71 is selectively removed, and the trace amount of nitrogen is removed. A wiring member 12 made of Al or the like is selectively formed so as to cover the surface of the silicon layer 14 contained therein.

FIG. 2 is an example of Auger analysis data obtained by measuring the amount of change in silicon Si, nitrogen N, and oxygen O while performing argon sputter etching on the surface of the silicon layer 14 containing a trace amount of nitrogen formed at the electrode contact portion. It is clear that a trace amount of nitrogen remains on the surface of the silicon layer 14.

With this configuration, like the semiconductor integrated circuit device shown in FIG.
A Schottky junction is formed in the electrode contact portions 41, 61, and 71, and an ohmic junction is formed in the electrode contact portions 41, 61, and 71, and a bipolar semiconductor integrated circuit in which a Schottky diode is clamped between the base and collector of an npn transistor is formed. A device is obtained.

FIG. 3 is a characteristic diagram showing the relationship between the hfe (high frequency current amplification factor) and the silane/ammonia ratio of the npn transistor in the bipolar semiconductor integrated circuit device constructed in this manner before and after the formation of the silicon nitride film. The solid line A shows an example of the characteristics before the formation of the silicon nitride film, and the broken line B shows the example of the characteristics after the formation of the silicon nitride film. As is clear from FIG. 3, hfe after silicon nitride film formation is smaller than the value before silicon nitride film formation when the silane/ammonia ratio is approximately 0.1, and when the silane/ammonia ratio is approximately 0.2. In the case of , the value is larger than the value before the silicon nitride film was formed.
In addition, when the silane/ammonia ratio is approximately 0.05, the composition ratio of Si and N in the silicon nitride film is
The ratio of silane/ammonia is approximately 45:55.
In the case of 0.35, the silicon nitride film has a silicon-rich composition ratio of 55:45, and when linear integrated circuits were manufactured under the latter condition, extremely high quality and highly stable products were obtained. Also, resistivity 3
When we formed an Al Schottky diode using an n-type CZ substrate of ~6 Ω cm and compared one with and without a silicon nitride film, we found a difference in the reverse characteristics between the two. When silicon nitride film was not provided, soft breakdown occurred, but
When a silicon nitride film was provided, hard breakdown occurred.

As is clear from this, the silicon layer 14 containing a small amount of nitrogen is formed between the epitaxial layer 3 and the wiring member 1.
As a result, a semiconductor integrated circuit device having a Schottky diode of high quality and stable characteristics can be realized.

Furthermore, since the reaction between the epitaxial layer 3 and the wiring member 12 is suppressed in this way, it is possible to form a base and an emitter with shallow diffusion regions, which is also effective in increasing the speed.

(Effects of the Invention) As is clear from this, according to the present invention, a semiconductor integrated circuit device having a Schottky diode of high quality and stable characteristics can be realized with a relatively simple configuration and at low cost. , the practical effect is great.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention;
FIG. 2 is an example of analysis data of a silicon layer containing a trace amount of nitrogen in the device according to the present invention, and FIG. 3 is an example of hfe characteristics of a transistor in the device according to the present invention.
FIG. 4 is a configuration explanatory diagram showing an example of such a conventional semiconductor integrated circuit device. 1...p-type semiconductor substrate, 2...n ⁺ type buried region,
3...n type epitaxial layer, 4...n ⁺ type collector region, 5...p type insulation isolation region, 6...p type base region, 7...n ⁺ type emitter region, 8...
Oxide film, 13... Silicon nitride film, 14... Silicon layer containing a trace amount of nitrogen, 31, 41, 61, 71
...Electrode contact part.

Claims (1)

[Claims] 1. A semiconductor integrated circuit device including a Schottky diode, characterized in that a silicon layer containing a trace amount of nitrogen is formed below an electrode of the Schottky diode.