JP2688609B2 - Method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to a method for manufacturing a semiconductor device in which a light receiving element section and an amplification element section are formed on the same substrate.

[Background of the Invention]

In the phototransistor light receiving system, a photodiode is used which has a good linearity and a good response speed with respect to incident light. However, since this photodiode has low light receiving sensitivity, a transistor as an amplifier is connected to the subsequent stage. That is, the light receiving element structure is a composite element structure of a photodiode and a transistor. Therefore, in the manufacturing process, it is necessary to perform die bonding twice with two chips per one, and the process is complicated.

Therefore, if a semiconductor device (chip) in which a photodiode and a transistor are formed on one chip is used,
It is possible to fabricate a phototransistor light-receiving device by die-bonding once, but for that purpose, both must be formed on the same substrate.

[Problems to be solved by the invention]

However, since the resistance values of the substrates used for the photodiode and the transistor are different from each other, it is not possible to unify them on one of the substrates. Therefore, it is difficult to manufacture the semiconductor device (chip) for the above purpose.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a semiconductor device in which a plurality of elements such as a photodiode and a transistor are formed on the same substrate.

[Means for solving the problem]

Therefore, in the method for manufacturing a semiconductor device of the present invention, in the method for manufacturing a semiconductor device in which a light receiving element and an amplifying element are formed on the same substrate, an epitaxial layer having a specific resistance smaller than that of the substrate is grown on the substrate. And exposing the substrate by patterning and opening the epitaxial layer by anisotropic etching, and forming the anode region of the light receiving element by diffusion in the exposed substrate and at the same time amplifying the amplification region in the epitaxial layer. The device is characterized by including a step of forming a base region of the element by diffusion and a step of forming an emitter region in the base region by diffusion.

〔Example〕

Hereinafter, a method of manufacturing the thin film semiconductor device A according to the embodiment of the present invention will be described. 1 (a), (b) and (c) are explanatory views showing the process. First, a substrate 1 made of a silicon wafer having a crystal orientation <100> and a specific resistance (80 to 100 Ω · cm) suitable for a photodiode is provided with a specific resistance (5 to 8 Ω · cm) and a thickness suitable for a transistor. The epitaxial layer 2 having is grown (see FIG. 1 (a)).

Next, a part of the epitaxial layer 2 to be the photodiode is patterned and removed with an anisotropic etching solution to open a part of the surface of the substrate 1 (see FIG. 1 (b)). Thereafter, the anode diffusion to the substrate 1 in the opening portion and the base diffusion to the epitaxial layer 2 in the portion to be the transistor are simultaneously performed to perform the anode 3 and the base 4 diffusion.
Is formed, and further, an emitter diffusion is performed on a part of the base 4 to form an emitter 5 (see FIG. 1 (c)).

In addition, 6 is an insulating film made of a silicon oxide film, 7 is a cathode formed on the back surface, 8 is a buried region layer formed between the substrate 1 and the epitaxial layer 2, and 9 is a connection between the anode 3 and the base 4. Wiring, 10 is an emitter electrode, 11 is a collector electrode, and 12 is a collector wall that connects the collector electrode 11 and the buried region layer 8.

As described above, the semiconductor device A in which the photodiode and the transistor are incorporated on the same substrate of one chip is manufactured. FIG. 2 is an equivalent circuit diagram. In the semiconductor device A thus formed, the photodiode and the transistor can have a specific resistance value and thickness suitable for each.
Therefore, it is possible to prevent the characteristics of both of them from deteriorating from the characteristics of those formed on separate chips.

〔The invention's effect〕

As described above, according to the semiconductor device manufacturing method of the present invention, the photodiode and the transistor can be formed on the same substrate without deteriorating the characteristics of each. Therefore, by using this semiconductor device (chip), a phototransistor type semiconductor device can be manufactured by die bonding of one chip once, and the process can be simplified and the manufacturing cost can be reduced.

[Brief description of the drawings]

1 (a), (b), and (c) are explanatory views showing the manufacturing process of the semiconductor device of one embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of the semiconductor device. 1 ... Substrate, 2 ... Epitaxial layer, 3 ... Anode, 4 ... Base, 5 ... Emitter, 6 ... Insulating film, 7
...... Cathode, 8 …… Embedded region layer, 9 …… Wiring, 10 ……
Emitter electrode, 11 …… collector electrode, 12 …… collector wall.

Claims (1)

(57) [Claims] 1. A method of manufacturing a semiconductor device in which a light-receiving element and an amplifying element are formed on the same substrate, wherein a step of growing an epitaxial layer having a specific resistance smaller than that of the substrate on the substrate and a step of forming the epitaxial layer differently. Exposing the substrate by patterning by means of isotropic etching, and forming the anode region of the light receiving element in the exposed substrate by diffusion and simultaneously forming the base region of the amplification element in the epitaxial layer by diffusion A method of manufacturing a semiconductor device, comprising: a step of forming an emitter region in the base region by diffusion.