TWI447895B - Semiconductor circuit - Google Patents

Description

Semiconductor circuit

The present invention relates to a semiconductor circuit, and more particularly to a semiconductor circuit having a voltage stabilizing function of a voltage source line.

With the development of semiconductor technology, the production of integrated circuits continues to introduce more advanced process technology. Thereby, today's microelectronic circuits can be driven with a small current at a small potential difference to perform various application functions. Consumers are therefore enjoying high-tech products that are thinner, more efficient and less power-hungry.

In order to accurately control the operation state of the semiconductor circuit, there is a very high precision requirement for various electronic signals. In today's integrated circuit applications, an operational amplifier is taken as an example. In addition to the input signal to be amplified, the operational amplifier itself needs to be coupled to the voltage source line. The voltage source line is used to supply the electrical energy required by various electronic components to drive the electronic components to operate normally.

Typically these voltage source lines are global lines in a semiconductor circuit, and a single voltage source line needs to correspond to many electronic components (eg, amplifiers, converters, loads, etc.). The voltage source line must be continuously supplied with a stable rated voltage. If the voltage provided by the voltage source line is offset, the working conditions of various components may be disordered, resulting in malfunction or damage of the electronic device.

Generally, the voltage source line is usually electrically connected to a corresponding voltage stabilizing capacitor. The voltage stabilizing capacitor can stabilize the voltage supply of the voltage source line and improve the stability of the overall circuit. Generally, the capacitor component is too large and is not suitable. Generally, a semiconductor capacitor is used as a voltage stabilizing capacitor of the voltage source line.

Please refer to Figure 1. 1 is a schematic view of a prior art semiconductor circuit 1. As shown in FIG. 1, the semiconductor circuit 1 includes a substrate 10, a thin oxide layer 12, a polysilicon layer, and a voltage source rail. A semiconductor capacitor structure can be formed by a thin oxide layer 12 disposed on the substrate 10 and a polysilicon layer 14 further disposed on the thin oxide layer 12. This semiconductor capacitor acts as a stabilizing capacitor through the voltage source line 16 above the polysilicon layer 14.

However, the above-mentioned prior art voltage stabilizing capacitors provide a capacitor effect by using a substrate, and the voltage signal of the voltage source line will interfere with other electronic components on the substrate.

In addition, in the case of manufacturing, handling, or even normal operation of an electronic device, it is possible to accumulate static electricity inside the electronic device. When an unexpected electrostatic discharge phenomenon occurs, the generated electrostatic discharge current may flow around the internal working circuit of the electronic device, and these electrostatic discharge currents cause irreparable damage to the internal working circuit of the electronic device.

In the prior art, in order to avoid damage that the electrostatic discharge current may cause to the internal working circuit, an electronic circuit having an electrostatic discharge protection function is generally required. The ESD protection circuit is used to introduce a possible electrostatic discharge current into a specific ESD path to avoid damage to the delicate internal working circuit.

Please refer to Figure 2 and Figure 3. 2 is a schematic diagram of an electronic device 2 having a semiconductor circuit 20 for electrostatic discharge protection in the prior art. FIG. 3 is a schematic diagram showing the circuit structure of the semiconductor circuit 20 in FIG. As shown in FIG. 2, a diode circuit structure (semiconductor circuit 20) for electrostatic discharge protection is generally coupled between the signal input terminal Vin and the internal working circuit 22 in the electronic device 2. As shown in FIG. 3, the semiconductor circuit 20 includes a substrate 200 and a diode circuit structure 202. However, because the diode circuit structure 202 is disposed in the substrate 200, it also interferes with other components in the substrate 200.

The invention provides a semiconductor circuit having a voltage source function of a voltage source line or an electrostatic discharge protection circuit to solve the above problems.

One aspect of the present invention is to provide a semiconductor circuit having the function of stabilizing a voltage signal of a voltage source line.

According to a specific embodiment, the semiconductor circuit includes a substrate, a dielectric layer, a polysilicon layer, and a voltage source line. The dielectric layer is disposed on the substrate. The polysilicon layer is disposed on the dielectric layer. The polysilicon layer has a first doped region, a second doped region, and an intrinsic region between the first doped region and the second doped region. The voltage source line passes over the polysilicon layer. The polysilicon layer forms a voltage stabilizing capacitor through the first doping region, the second doping region and the intrinsic region, and the stabilizing capacitor is used to stabilize the pass voltage of the voltage source line, thereby improving the stability of the semiconductor circuit.

Another aspect of the present invention is to provide a semiconductor circuit having the function of an electrostatic discharge protection circuit.

According to a specific embodiment, the semiconductor circuit includes a substrate, a dielectric layer, and a polysilicon layer. The dielectric layer is disposed on the substrate. The polysilicon layer is disposed on the dielectric layer. The polysilicon layer has a first doped region, a second doped region, and an intrinsic region between the first doped region and the second doped region. The first doped region and the second doped region of the polysilicon layer form a diode structure, and the diode can be used as a discharge path for electrostatic discharge protection.

Compared with the prior art, the semiconductor circuit proposed by the present invention can be used as a voltage stabilizing capacitor of a voltage source line. In another application, it can also serve as a discharge path of an electrostatic discharge current. The semiconductor circuit of the present invention utilizes the polysilicon layer itself. The doping design is to form a stabilizing capacitor or an electrostatic discharge protection effect, and has a simple structure, convenient fabrication, small volume, and difficulty in causing interference to other components on the circuit substrate.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

Please refer to Figure 4 and Figure 5. 4 is a schematic diagram of a semiconductor circuit 3 in accordance with an embodiment of the present invention. FIG. 5 is a schematic side view of the semiconductor circuit 3 of FIG. As shown in FIGS. 4 and 5, the semiconductor circuit 3 includes a substrate 30, a dielectric layer 32, a polysilicon layer 34, and a voltage source line 36.

The dielectric layer 32 is disposed on the substrate 30. The polysilicon layer 34 is further disposed on the dielectric layer 32. Dielectric layer 32 can be a thin oxide layer or a field oxide layer. Generally, the oxide layer of the field oxide layer is thicker than the thin oxide layer. In practical applications, the field oxide layer is usually placed on the circuit board where the circuit is less dense, which can provide A good electrostatic isolation effect prevents the substrate 30 from being disturbed by noise and affects other components disposed on the substrate 30. The dielectric layer 32 is exemplified by the field oxide layer. However, the dielectric layer 32 of the present invention can also achieve similar effects for the oxide layers of different thicknesses, and is not limited to the field oxide layer.

The polysilicon layer 34 is a polysilicon material which is disposed over the dielectric layer 32 by a polysilicon gate process commonly employed in current integrated circuits. In this embodiment, the first doped region 340 and the second doped region 342 are formed by doping in the polysilicon layer 34 of the present invention. Between the first doped region 340 and the second doped region 342 is an intrinsic region 344 of the polysilicon layer 34.

The voltage source line 36 passes over the polysilicon layer 34. The voltage source line 36 is a source of electrical energy for the semiconductor circuit 3 for electrically driving other electronic components (not shown) in the semiconductor circuit 3.

In this embodiment, the voltage source line 36 can be a high voltage source line (Vdd line in an electronic circuit), a low voltage source line (Vss line), or a ground line (GND line). The grounding wire here is not limited to a substantial earth-ground. The grounding wire here can be a digital-ground used in an electronic circuit for use as a reference voltage zero point in an electronic circuit. . Voltage source line 36 has a pass voltage. In general, current semiconductor circuit components have extremely high sensitivity to signals, and in particular analog or high frequency components require a high quality and stable power supply.

The first doped region 340 of the polysilicon layer 34 has a first doping type, and the second doping region 342 has a second doping type, and the first doping region 340 is opposite to the doping type of the second doping region 342. For example, the first doping region 340 is a hole type (P type) doping, and the second doping region 342 is an electron type (N type) doping. borrow Thus, the two doped regions of the polysilicon layer 34 can form a circuit structure of the diode. At the same time, the diode also produces a parasitic capacitor effect. That is, the polysilicon layer 34 forms a diode parasitic capacitance through the first doping region 340, the second doping region 342, and the intrinsic region 344 as a stabilizing capacitor that stabilizes the pass voltage of the voltage source line 36.

In summary, the semiconductor circuit structure of the present invention forms different doped regions in the polysilicon layer to achieve the effect of stabilizing capacitance, and the polysilicon layer is disposed on the dielectric layer, and the polysilicon layer is not directly connected to the substrate. And the dielectric layer provides an insulating effect between the polysilicon layer and the substrate. Therefore, the diode formed by the polysilicon layer serves as a voltage stabilizing capacitor of the voltage source line, which can reduce interference with other electronic components on the substrate.

Please refer to Figure 6. Figure 6 is a side elevational view of a semiconductor circuit 5 in accordance with an embodiment of the present invention. As shown in FIG. 6, the semiconductor circuit 5 includes a substrate 50, a dielectric layer 52, and a polysilicon layer 54. The dielectric layer 52 is disposed on the substrate 50. Dielectric layer 52 can be a thin oxide layer or a field oxide layer.

A polysilicon layer 54 is disposed on the dielectric layer 52. The polysilicon layer 54 has a first doped region 540, a second doped region 542, and an intrinsic region 544 between the first doped region and the second doped region. The first doped region 540 of the polysilicon layer 54 has a first doping type, and the second doping region 542 has a second doping type, and the first doping region 540 is opposite to the doping type of the second doping region 542. In this embodiment, the first doping region 540 is a hole type (P type) doping, and the second doping region 542 is an electron type (N type) doping. The first doped region 540 and the second doped region 542 of the polysilicon layer 54 form a diode structure, which can be used as a discharge path for electrostatic discharge protection.

In this embodiment, the first doping region 540 is P-type doped, so the terminal end 56a electrically connected to the first doping region 540 can be regarded as a diode anode, and on the other hand, the first doping region. The end point 56b of the 542 electrical connection can be considered a diode cathode.

Please refer to Figure 7 together. FIG. 7 is a schematic circuit diagram of the semiconductor circuit 5 of FIG. 6 when it is used for an electrostatic protection function. As shown in FIG. 7, the semiconductor circuit 5 can be coupled between the high voltage source line Vdd and the signal input terminal Vin. If an abnormal electrostatic discharge occurs in the signal input terminal Vin, the voltage at the signal input terminal is instantaneously higher than the normal rated high voltage of the system (ie, Vdd) plus the startup voltage of the diode (usually 0.7 volts), then the semiconductor circuit 5 The formed diode is forward biased and the excessive voltage of the signal input terminal Vin is guided to the high voltage source line Vdd to achieve an electrostatic discharge protection function to avoid harming the internal working circuit 6.

Similarly, the semiconductor circuit 5 can also be coupled between the signal input terminal Vin and the low voltage source Vss. Similarly, the protection function can be activated when the voltage at the signal input is instantaneously lower than the normal rated low voltage (ie, Vss) of the system. Thereby, the input range of the internal working circuit 6 can be ensured to be within a certain interval, and the internal working circuit 6 can be prevented from being damaged due to abnormal changes of the input signal.

In summary, the semiconductor circuit structure of the present invention forms different doped regions in the polysilicon layer to form a diode circuit structure, and the polysilicon layer is disposed on the dielectric layer, and the polysilicon layer is not directly connected to the substrate, and This dielectric layer provides an insulating effect between the polysilicon layer and the substrate. Therefore, the diode formed by the polysilicon layer acts as a discharge path for electrostatic discharge, which can reduce the pair Interference from other electronic components on the substrate.

Compared with the prior art, the semiconductor circuit proposed by the present invention can be used as a voltage stabilizing capacitor of a voltage source line. In another application, it can also serve as a discharge path of an electrostatic discharge current. The semiconductor circuit of the present invention utilizes the polysilicon layer itself. The doping design is to form a stabilizing capacitor or an electrostatic discharge protection effect, and has a simple structure, convenient fabrication, small volume, and difficulty in causing interference to other components on the circuit substrate.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

1, 20, 3, 5‧‧‧ semiconductor circuits

2‧‧‧Electronic devices

202‧‧‧Diode circuit structure

10, 200, 30, 50‧‧‧ substrates

22, 6‧‧‧ internal working circuit

12, 32, 52‧‧‧ dielectric layer

14, 34, 54‧‧‧ polycrystalline layer

16, 36‧‧‧voltage source line

340, 540‧‧‧ first doped area

342, 542‧‧‧Second doped area

344, 544‧‧‧ Essential Area

56a, 56b‧‧‧ endpoint

Vin‧‧‧ signal input

Vdd‧‧‧High voltage source line

Vss‧‧‧ low voltage source line

1 is a schematic diagram of a semiconductor circuit in the prior art.

2 is a schematic diagram of an electronic device having a semiconductor circuit for electrostatic discharge protection in the prior art.

FIG. 3 is a schematic diagram showing the circuit structure of the semiconductor circuit in FIG.

4 is a top plan view of a semiconductor circuit in accordance with an embodiment of the present invention.

FIG. 5 is a side view showing the semiconductor circuit of FIG.

6 is a side elevational view of a semiconductor circuit in accordance with an embodiment of the present invention.

FIG. 7 is a schematic circuit diagram of the semiconductor circuit of FIG. 6 when used for an electrostatic protection function.

3‧‧‧Semiconductor circuit

30‧‧‧Substrate

32‧‧‧Dielectric layer

34‧‧‧Polysilicon layer

36‧‧‧Voltage source line

340‧‧‧First doped area

342‧‧‧Second doped area

344‧‧‧ Essential Area

Claims (6)

A semiconductor circuit is disposed between a voltage source line and a signal input end and coupled to an internal working circuit, the semiconductor circuit comprising: a substrate; a dielectric layer disposed on the substrate; and a polysilicon layer Provided on the dielectric layer, having a first doped region, a second doped region, and an intrinsic region between the first doped region and the second doped region, the voltage source a line passes over the polysilicon layer; wherein a first doping type of the first doping region is opposite to a second doping type of the second doping region, such that the first doping region and the second doping region The stabilizing region forms a diode and the polysilicon layer forms a stabilizing capacitor through the first doping region, the second doping region and the intrinsic region, and the stabilizing capacitor is configured to stabilize one of the voltage source lines Voltage, the voltage source line is a high voltage source line. If an abnormal electrostatic discharge occurs at the signal input end, the instantaneous voltage of one of the signal inputs is higher than the normal rated high voltage of the system plus the starting voltage of the diode. The diode is forward biased and the signal input The high instantaneous voltage to the voltage source line guide, to protect the internal circuitry. The semiconductor circuit of claim 1, wherein the dielectric layer is a thin oxide. The semiconductor circuit of claim 1, wherein the dielectric layer is a field oxide. a semiconductor circuit disposed on a voltage source line and a signal input end And interposing an internal working circuit, the semiconductor circuit comprising: a substrate; a dielectric layer disposed on the substrate; and a polysilicon layer disposed on the dielectric layer having a first doping a region, a second doped region, and an intrinsic region between the first doped region and the second doped region, the voltage source line passing over the polysilicon layer; wherein the first doped region a first doping type is opposite to a second doping type of the second doping region, such that the first doping region and the second doping region form a diode and the polysilicon layer passes through the first doping The stabilizing region, the second doping region and the intrinsic region form a voltage stabilizing capacitor, wherein the stabilizing capacitor is configured to stabilize a voltage passing through one of the voltage source lines, and the voltage source line is a low voltage source line, when the signal is input When one of the terminals is lower than the normal rated low voltage of the system, the diode can be activated to maintain the input range of the internal working circuit within a certain voltage range to protect the internal working circuit. The semiconductor circuit of claim 4, wherein the dielectric layer is a thin oxide. The semiconductor circuit of claim 4, wherein the dielectric layer is a field oxide.