JPS61270864A - Monolithic element provided with silicon ic and light-emitting element - Google Patents

Abstract

PURPOSE:To obtain a miniature, precise and microscopic device provided with an silicon IC and a light-emitting element by a method wherein the light-emitting element is provided on the Si substrate, wherein the silicon IC is integrated, and the light-emitting element is connected with the IC. CONSTITUTION:An IC21 and a diffusion resistor 26 are formed in a P-type Si substrate 20. An SiO2 film 28 is opened on the resistor 26, a compound semi conductor material, such as AlGaAS, is made to grow and a P-N junction LED22 is formed. Then, electrical and optical element isolation regions 23 are provided using a polyimide resin, an opening is formed on an insulating film 27, and a wiring 24 between the IC21 and the LED22 and an electrode pad 25 are provided. According to this constitution, when these monolithic elements are constituted in an LED array, the intervals between the mutually adjoining light-emitting parts can be shortened because wire connection is unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a monolithic device comprising a silicon IC and a light emitting element.

(Prior Art) Conventionally, a light emitting element (LED) array element, which is an element in which one light emitting element, for example, seven light emitting diodes, are monolithically arranged in a array, has been used as a light source in the head of an optical printer or a display device. In these devices, each light emitting part of the LED array must operate independently, and a drive circuit is required for its operation.For example, an optical writing head of a photo printer is constructed using an LED array. In this case, an optical writing circuit section shown in a block diagram in Figure 1s4 is required.

゛ This optical writing circuit converts the pixel data read by the sensor into parallel data using the serial/parallel converter 10, stores this parallel data in the -H memory 11, and transfers it to the drive circuit 13 in the data distribution circuit 12. The data is distributed and the corresponding LED 14 is controlled to emit light.

This drive circuit section 13 includes a register 15 and a driver 1B, and is usually implemented as an IC. This drive circuit ICl3
is formed by a silicon IC (hereinafter also referred to as 5iIC), and the LED 14 is mainly made of GaAlAs or Ga.
It is manufactured using AsP or other compound semiconductor materials. Then, this 5i IC and the LED were connected in a hybrid manner by a wire bonding method.

(Problems to be Solved by the Invention) However, since such a hybrid element is connected by wire bonding, the size of the light emitting part is limited by the size of the bonding pad. For this reason, there has been a problem in that it is difficult to achieve high definition and miniaturization of devices such as LED arrays and therefore optical printer heads.

Furthermore, since it is a hybrid element of an S[IC and a compound semiconductor element, there are problems in that, for example, the yield due to the connection work between the two is poor, and it is difficult to reduce the manufacturing cost of the hybrid element itself.

An object of the present invention is to provide a monolithic device consisting of a 5t IC and a light emitting element, which has a structure that allows not only the LED array itself but also devices such as an optical printer head to be made high-definition and compact, and to reduce manufacturing costs.

(Means for Solving the Problems) In order to achieve this object, according to the monolithic device of the present invention, which includes a silicon IC and a light emitting element, a light emitting element is mounted on a silicon substrate in which a 5i IC is incorporated and which has a flat surface. The 5i IC is electrically connected to a light emitting element.

(Function) In this way, since the 5iIC is a monolithic element in which the light emitting element is formed on the flat surface of the Si substrate on which it is formed, the connection work can be formed using normal semiconductor technology without using the wire bonding method. . Therefore, when configured as an LED array, the distance between adjacent light emitting parts can be shortened, and moreover, it is possible to manufacture a compact and high-definition device such as an optical printer head.

Further, according to the structure of the monolithic element of the present invention, it can be formed without requiring connection work such as wire bonding, so the manufacturing yield is improved, and as a result, it can be manufactured at low cost and a highly reliable element can be obtained. .

(Embodiments) Hereinafter, embodiments of the present invention will be described in terms of light emitting element arrays with reference to the drawings.It should be noted that these figures are only schematic illustrations to the extent that the invention can be understood. The dimensions, shapes, and arrangement relationships of the components are not limited to the illustrated examples described below.

FIG. 1 is a cross-sectional view schematically showing an embodiment of the structure of a monolithic device including a silicon IC and a light emitting device according to the present invention, which constitutes a part of a light emitting device array.

In the figure, 20 is a silicon substrate, in this case p-
It is assumed to be a 3L board. The structure of this Si substrate may be a single Si substrate, a substrate formed by providing a Si epitaxial layer on a single Si substrate, or a substrate with another structure, and its structure and manufacturing method are not limited. .

This Si substrate 20 has a flat surface, and includes a 5i IC 21 in which a driving circuit for driving a light emitting element is formed into an IC. The method for manufacturing this IC21 is not limited.

22 is a light emitting element (LED) formed on this St substrate 20.
)22.

Reference numeral 23 denotes an element isolation layer for optically and electrically isolating adjacent light emitting elements 22 and electrically isolating 1 light emitting element 22 and 5i IC 21. For example, this element isolation layer 23 is provided around the light emitting element 22. It is provided on the substrate 20 of.

24 is a wiring portion connecting the light emitting element 22 and the 5i IC 21, and 25 is an electrode pad. 2B is light emitting element 2
2 and between the light emitting element 22 and the 5i IC 21 in the surface area of the substrate 20. This diffused resistor 2B forms an ohmic contact with the light emitting element 22, performs insulation separation from the Si substrate 20, and
This is to form a resistance between the 5ilC21 and the 5ilC21.

27 is an insulating layer provided on the 5i IC 21 and other appropriate parts of the substrate 20.

In this monolithic element structure, as mentioned above, the 5iIC, which is the drive circuit for the light emitting element (LED) array,
LED 2 formed on the p-3i substrate 20 with built-in LED 21
2 are optically isolated from each other by an element isolation layer 23, and in addition, wiring with S, i I C 21 is also electrically isolated by this element isolation layer 23. Further, the electrical connection of the L E D 22 to the n-side 5i IC 21 is performed by a diffused resistor 26 .

As a result, as shown in the equivalent circuit diagram of FIG.
The monolithic element is electrically connected to the ED 22 through a resistance (diffused resistance) of 2G. This LED driving circuit S i I C 21 also includes a register 15 shown in FIG. 4 . This resistor 26 is connected to the LED 22 and 5i
It functions to absorb characteristic fluctuations with IC21.

Next, a method for manufacturing this monolithic element will be briefly described with reference to FIGS. 3(A) to 3(C). Furthermore, the first
Components that are the same as those shown in the figures are indicated by the same reference numerals.

First, the Si IC 21 and the diffused resistor 28 are provided on the P-SI substrate 20 by a conventional method. Furthermore, LED22
A mask 28 is formed by a conventional method on the surface of the substrate except for the area where the mask 28 is to be formed (FIG. 3A). The mask 28 is made of, for example, 5iOz, SiN, or other suitable insulating film.

Next, a p-n junction LED 22 is selectively formed (third
Figure (B)), the material of this LED 22 is MGaA
In addition to compound semiconductor materials such as S, GaASP, etc., Zn
For example, on a Sl substrate, MBE or MO
It is known that it is possible to grow GaAs, AQGaAs, etc. by the CVD method (for example, literature: "Journal of Crystal Growth").
of Cr7stalGrowth) J, 88,
(1), (11384), P21-2B), using such a growth method to grow jlaGaAs or GaAsP.
A pn junction can be formed.

Next, electrical and optical element isolation regions 23 are formed using, for example, polyimide resin, and wiring portions 24 are
22 and the 5i IC 21, and further an electrode, that is, an electrode pad 25 is provided. These formations can be performed in a conventional manner. The wiring portion 24 and the electrode 25 are separated by an insulating layer 27.

In this way, the device of the present invention has a structure in which 5ilC and a light emitting device are monolithically integrated, and therefore,
With this structure, the 5ilC and the light emitting element can be formed using conventional semiconductor technology without using the wire bonding method.

In the above-mentioned embodiments, the case where an LED array is mainly manufactured has been explained, but the device of the present invention can be applied by using the device itself as a carrier.

In addition, in the above embodiment, the structure is such that the 5i IC is built into the p-type substrate, and the LED is built on this substrate.
It is also possible to adopt a structure in which the substrate is n-type and the conductivity types of each component are inverted correspondingly.

Furthermore, the pn junction of the LED can not only be formed by the above-mentioned growth method, but also by a diffusion method.

(Effects of the Invention) As is clear from the above description, according to the silicon IC and the monolithic light emitting element of the present invention, wire bonding is not used, so the size of the light emitting part is not limited. Maybe it's time to get a highly reliable device.
Therefore, when creating an LED array, adjacent LEDs
It is possible to arrange them close together, so that
It is possible to realize a high-definition LED array in a simple manner.

Furthermore, by using this LED array, various devices including optical printer heads can be made smaller and have higher definition.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a monolithic device including a silicon IC and a light emitting device according to the present invention, FIG. 2 is an equivalent circuit diagram of the structure of this monolithic device, and FIG. 3 is a monolithic device according to the present invention. FIG. 4 is a manufacturing process diagram for explaining the manufacturing method of one embodiment of the present invention, and FIG. 4 is a block diagram showing an optical writing circuit section. 20...Si substrate, 21...5iIC
22...Light emitting element (LED), 23...Element gl
! 24... Wiring part, 25... Electrode pad 28... Diffused resistance, 27... Insulating layer 2
8...Mask. Patent Applicant Oki Electric Industry Co., Ltd. Agent Patent Attorney Takashi Ogaki 20: Si Curtain Board 2f: 5ilC 22: Light Rope (LEυn 23: I1 Bit 1 24; Wiring (P 25: 4Dh Bar 1 Do 26) : 4 μ other resistance 27: absolute repair 1 S i I (:' トLEf) ttf) eノ') Schiff happiness %tyy failure 1! Jl Figure 1) Year 4-b Words D〕 Figure 2/J Death) Kikomi times Exaggeration Figure 4 Vomit a 2 Vomiting Figure 3

Claims (1)

[Claims] (1) Silicon I characterized by having a light emitting element on a silicon substrate having a flat surface in which a silicon IC is incorporated, and electrically connecting the silicon IC and the light emitting element.
A monolithic device consisting of C and a light emitting element.