JPH0823072A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device equipped with a circuit where two resistors, at least, are connected together, wherein the resistors are so constituted as to be kept constant in a resistance relative ratio between them independent of the potentials of the terminals of the resistors. CONSTITUTION:The man-connecting terminal of a resistor is connected to both diffusion resistor sections 2 which form a resistor and semiconductors 3 which are provided surrounding the diffusion resistor sections 2, the connecting terminal of the resistor is connected to the diffusion resistor sections 2 of the connected resistors, and the semiconductors 3 provided surrounding the diffusion resistors 2 of the connected resistors are connected to each other and separated from the connection terminal of the resistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a circuit in which at least two resistors are connected to each other.

[0002] In recent years, along with the expansion of applications of analog / digital mixed LSI, there is a demand for high precision and low distortion characteristics of analog circuits. Therefore, it is required to accurately create a relative ratio of a plurality of resistors. That is, it is required to create a resistor in which the relative ratio of a plurality of resistors does not change due to a change in the voltage of the resistor terminals.

[0003]

2. Description of the Related Art FIGS. 9 and 10 show a state in which two resistors formed on a semiconductor device are connected to each other.
9 (a) and 10 (a) show cross-sectional views, and FIG. 9 (b).
And FIG. 10 (b) shows a plan view. In these figures,
Reference numeral 2 is a diffusion resistance portion, and 3 is a semiconductor portion surrounding the diffusion resistance portion 2. The semiconductor portion 3 surrounding the diffusion resistance portion 2 is
In FIG. 9, they are separated by a well structure, and in FIG. 10, they are separated by an insulating layer 6 formed on the bottom surface and a diffusion layer 7 of the opposite conductivity type formed on the side wall. .

The terminals A and C provided at the non-connection ends where the two resistors are not connected to each other have contacts 4 of the diffusion resistance portion 2 and contacts of the semiconductor portion 3 surrounding the diffusion resistance portion 2. 5 is connected to the terminal 5 and the terminal B provided at the connection part where the two resistors are connected to each other is
It is connected to the contact 4 of the diffusion resistance part 2 of two resistors and the contact 5 of the semiconductor part 3 surrounding the diffusion resistance part 2, respectively.

A circuit diagram of this is shown in FIG.

[0006]

In FIG. 9, for example, when a voltage of 0 V is applied to the terminal A and a voltage of 5 V is applied to the terminal C, the diffusion resistance portion 2 between the terminals A and B and between the terminals B and C is surrounded. A potential gradient is generated in the semiconductor section 3. As a result, a potential difference occurs between the semiconductor portion 3 surrounding the diffusion resistance portion 2 and the semiconductor layer 1, but this potential difference is small on the terminal A side and large on the terminal C side. Therefore, the width of the depletion layer generated on the junction surface of the semiconductor portion 3 surrounding the diffusion resistance portion 2 with the semiconductor layer 1 is small on the terminal A side and large on the terminal C side. As a result, the resistance of the semiconductor portion 3 surrounding the diffusion resistance portion 2 between the terminals B and C is higher than the resistance of the semiconductor portion 3 surrounding the diffusion resistance portion 2 between the terminals A and B. In the circuit diagram shown in FIG. 12, when the resistance values of the semiconductor portion 3 surrounding the two diffusion resistance portions 2 are different, even if the resistances of the two diffusion resistance portions 2 are equal, the terminals A and B and the terminal B. The relative ratio of resistance between C varies.

The same applies to FIG. 10, and the width of the depletion layer at the junction between the semiconductor portion 3 surrounding the diffusion resistance portion 2 and the diffusion layer 7 of the opposite conductivity type for isolation is unequal in correspondence with the potential gradient. The resistance of the semiconductor portion 3 surrounding the diffusion resistance portion 2 between the terminals A and B and between the terminals B and C is different. As a result,
As in the case of, the relative ratio of the resistance between the terminals A and B and between the terminals B and C changes.

An object of the present invention is to eliminate this drawback. In a semiconductor device having a circuit in which a plurality of resistors are connected, the relative ratio of the resistors is not changed by the potential of the terminals of the resistors. The present invention is to provide a semiconductor device.

[0009]

The above object is to provide a semiconductor device having a circuit in which at least two resistors are connected to each other, and a terminal at a non-connection end of the resistor constitutes the resistor. It is connected to both the diffusion resistance portion 2 and the semiconductor portion 3 surrounding the diffusion resistance portion 2, and the terminal of the connection portion of the resistance is connected to the diffusion resistance portion 2 of both resistances to be connected. This is achieved by a semiconductor device in which the semiconductor parts 3 surrounding the diffused resistance part 2 of both the resistances connected to each other are connected to each other, but are separated from the terminals of the connection part of the resistances. It The semiconductor part 3 surrounding the diffusion resistance part 2 is preferably separated from other semiconductor parts so as to be electrically given an arbitrary potential. The semiconductor portion 3 surrounding 2 has a well structure having a conductivity type opposite to that of the diffusion resistance portion 2, or the bottom surface is separated by an insulating layer 6 and the side surface is formed into the diffusion resistance portion 2 described above.
Is preferably separated by a diffusion layer 7 having a conductivity type opposite to the conductivity type of the semiconductor portion 3 surrounding the.

The at least two diffusion resistance portions may be surrounded by one semiconductor portion, and the at least two diffusion resistance portions may be integrally formed and formed integrally. At least 3 from the diffusion resistance part
It is also possible to have a structure in which one terminal is taken out, and the at least two diffusion resistance portions are provided side by side in a direction crossing a line connecting between two contacts formed in the semiconductor portion surrounding the diffusion resistance portion. Further, the diffusion resistance portion may be a bent portion, and a potential gradient in the same direction as a potential gradient generated between two contacts formed in a semiconductor portion surrounding the diffusion resistance portion. The structure may be bent so as to generate.

[0011]

In FIG. 1 and FIG. 2, when a voltage is applied between the terminals A and C, almost the same potential gradient is generated in the diffusion resistance section 2 and the semiconductor section 3 surrounding the diffusion resistance section 2. Therefore, the diffusion resistance portion 2 and the semiconductor portion 3 surrounding the diffusion resistance portion 2
A potential difference hardly occurs over the entire area at the joint surface with. Therefore, the width of the depletion layer of this junction surface hardly changes over the entire region, so that the resistance value of the diffusion resistance portion 2 is kept substantially constant even when a voltage is applied. On the other hand, although the resistance value of the semiconductor portion 3 surrounding the diffusion resistance portion 2 changes depending on the voltage applied between the terminals A and C as described in the conventional example, the semiconductor portion 3 surrounding the diffusion resistance portion 2 is Since the interconnecting wires are not connected to the terminal B as shown in FIG. 11, even if the resistance value of the semiconductor portion 3 surrounding the diffusion resistance portion 2 changes, the resistance between the terminals A and B and between the terminals B and C is reduced. The relative ratio is kept constant without affecting the relative resistance ratio.

[0012]

The shapes of resistors according to eight embodiments of the present invention will be described below with reference to the drawings.

First Example See FIG. 1 FIG. 1 (a) is a sectional view and FIG. 1 (b) is a plan view. In the figure, 1 is, for example, a p-type semiconductor layer, 2 is a p-type diffusion resistance portion, 3 is a semiconductor portion surrounding the diffusion resistance portion 2, and is an n-type well. Reference numeral 4 is a contact formed in the p-type diffusion resistance portion 2, 5 is a contact formed in the n-type well 3, and 8 is a wiring.

The terminals A and C at both ends are respectively connected to the contact 4 of the p-type diffused resistance portion 2 and the contact 5 of the n-type well 3 via the wiring 8, and the terminal B of the central connection portion is
It is connected to the contacts 4 of the two left and right p-type diffusion resistance portions 2 via the wiring 8. In the central connection part, the contacts 5 of the two semiconductor parts 3 surrounding the diffusion resistance part 2 are connected to each other via the wiring 8, but are separated from the terminal B.

Second Example See FIG. 2 FIG. 2A is a sectional view and FIG. 2B is a plan view. In the figure, 2 is a diffusion resistance portion, 3 is a semiconductor portion surrounding the diffusion resistance portion 2, 6 is an insulating layer, and 7
Is a diffusion layer for isolation having a conductivity type opposite to that of the semiconductor portion 3 surrounding the diffusion resistance portion 2. The wiring connection is the same as in the first example.

Third Example See FIG. 3 FIG. 3 (a) is a sectional view and FIG. 3 (b) is a plan view. The two wells 3 in the first example are combined to form one well 3, and two diffusion resistance portions 2 are formed therein.

Fourth Example See FIG. 4 FIG. 4A is a sectional view and FIG. 4B is a plan view. The two diffusion resistance portions 2 in the third example are combined into one, and one diffusion resistance portion 2 is formed with three contacts 4 respectively connected to the terminals A, B, and C.

Fifth Example See FIG. 5 FIG. 5 (a) is a sectional view and FIG. 5 (b) is a plan view. The two diffusion resistance portions 2 in the second example are combined to form one, and one diffusion resistance portion 2 is formed with three contacts 4 respectively connected to the terminals A, B, and C. .

Sixth Example See FIG. 6 A plurality of diffusion resistance portions 2 (five in this drawing) are formed in one well 3, and these diffusion resistance portions 2 are two contacts provided in the well 3. They are provided side by side in the direction intersecting with the line connecting 5 and in the direction orthogonal to this example.

Seventh Example See FIG. 7 A diffusion resistance portion 2 is formed in a bent manner in one well 3. The bent portion is formed so that there is no portion in which the potential gradient generated in the bent portion is in the opposite direction to the potential gradient generated between the two contacts 5 formed in the well 3.

Eighth Example See FIG. 8 FIG. 8 shows a circuit diagram when the resistor according to the present invention is applied to an inverting amplifier. In the figure, 2 is the resistance of the diffusion resistance portion, 3 is the resistance of the semiconductor portion surrounding the diffusion resistance portion 2, and the voltage division ratio at the voltage dividing point P is always kept constant.

[0022]

As described above, in the semiconductor device according to the present invention, the diffusion resistance portions and the semiconductor portions surrounding the diffusion resistance portions are separated from each other in the connection portion connecting the two resistors to each other. Since the terminals are taken out only from the connection wiring of the diffusion resistance part, the resistance ratio of each resistance does not change even if the potential of each terminal changes, and a highly accurate resistance ratio can be obtained. This contributes to high precision and low distortion of the analog circuit in the semiconductor device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a resistor according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a resistor according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a resistor according to a third exemplary embodiment of the present invention.

FIG. 4 is a configuration diagram of a resistor according to a fourth exemplary embodiment of the present invention.

FIG. 5 is a configuration diagram of a resistor according to a fifth exemplary embodiment of the present invention.

FIG. 6 is a configuration diagram of a resistor according to a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram of a resistor according to a seventh embodiment of the present invention.

FIG. 8 is a circuit diagram when the resistor according to the present invention is applied to an inverting amplifier.

FIG. 9 is a configuration diagram of a resistor according to a conventional technique.

FIG. 10 is a configuration diagram of a resistor according to a conventional technique.

FIG. 11 is a circuit diagram of a resistor according to the present invention.

FIG. 12 is a circuit diagram of a resistor according to the related art.

[Explanation of symbols]

1 semiconductor layer 2 diffusion resistance part 3 semiconductor part surrounding the diffusion resistance part 4 contact 5 formed in the diffusion resistance part contact 5 formed in the semiconductor part surrounding the diffusion resistance part 6 insulating layer 7 separation diffusion layer 8 wiring

Claims (8)

[Claims] 1. A semiconductor device having a circuit in which at least two resistors are connected to each other, wherein a terminal at a non-connection end of the resistors surrounds a diffusion resistance part forming the resistance and the diffusion resistance part. The resistor is connected to both sides of the semiconductor part, and the terminal of the resistor connecting part is connected to the diffused resistor part of both connected resistors, and surrounds the diffused resistor part of both connected resistors. The semiconductor device is connected to each other and is separated from the terminal of the connection portion of the resistor. 2. The semiconductor portion surrounding the diffusion resistance portion,
2. The semiconductor device according to claim 1, wherein the semiconductor device is separated from other semiconductor parts so that an arbitrary potential is electrically applied. 3. The semiconductor portion surrounding the diffusion resistance portion,
3. The semiconductor device according to claim 2, wherein the well has a conductivity type opposite to that of the diffusion resistance portion. 4. The semiconductor portion surrounding the diffusion resistance portion,
3. The semiconductor device according to claim 2, wherein the bottom surface is separated by an insulating layer, and the side surface is separated by a diffusion layer having a conductivity type opposite to that of the semiconductor portion surrounding the diffusion resistance portion. 5. The semiconductor device according to claim 1, wherein the at least two diffusion resistance parts are surrounded by one semiconductor part. 6. The at least two diffusion resistance parts are integrally formed, and at least three terminals are taken out from the integrally formed diffusion resistance parts. 3. The semiconductor device according to 3 or 4. 7. The at least two diffusion resistance portions are provided side by side in a direction intersecting a line connecting two contacts formed in a semiconductor portion surrounding the diffusion resistance portions. The semiconductor device of 1, 2, 3, 4, or 5. 8. The diffusion resistance portion is formed of a bent portion, and is bent so that a potential gradient is generated in the same direction as a potential gradient generated between two contacts formed in a semiconductor portion surrounding the diffusion resistance portion. 7. The semiconductor device according to claim 1, 2, 3, 4, or 6.