Poly silicon resistor, reference voltage circuit comprising the same, and manufacturing method of poly silicon resistor

1. A polysilicon resistor comprising:

a first polysilicon resistor, and

at least one of second polysilicon resistors coupled to the first polysilicon resistor in series,

wherein the first polysilicon resistor and the at least one of the second polysilicon resistors comprise P-type polysilicon, a doping concentration of the first polysilicon resistor is different from a doping concentration of the at least one of the second polysilicon resistors, and the first polysilicon resistor includes a region that is not doped with P-type impurities.

2. The polysilicon resistor of claim 1 , further comprising a substrate and first and second oxide layers formed on the substrate,

wherein the first polysilicon resistor comprises first gate polysilicon formed on the first oxide layer, one of the at least one of the second polysilicon resistors comprises second gate polysilicon formed on the second oxide layer, and an insulating layer is formed between the first and second oxide layers and between the first polysilicon resistor and the at least one of the second polysilicon resistors.

3. The polysilicon resistor of claim 2 , wherein a doping concentration of the first gate polysilicon is different from a doping concentration of the second gate polysilicon.

4. The polysilicon resistor of claim 3 , wherein an area of the first gate polysilicon, doped with P-type impurities and an area of a region of the second gate polysilicon, doped with the P-type impurities are different from each other.

5. The polysilicon resistor of claim 2 , further comprising:

first and second contacts formed on the first gate poly region; and

third and fourth contacts formed on the second gate poly region.

6. The polysilicon resistor of claim 5 , wherein the region of the first gate polysilicon, doped with the P-type impurities is a region corresponding to the first and second contacts.

7. The polysilicon resistor of claim 5 , further comprising a first metal electrode formed on the second and third contacts and connecting the second contact and the third contact with each other.

8. The polysilicon resistor of claim 7 , further comprising:

a second metal electrode formed on the first contact and connected to the first contact; and

a third metal electrode formed on the fourth contact and connected to the fourth contact.

9. The polysilicon resistor of claim 8 , wherein the width of the first metal electrode is greater than the width of each of the second and third contacts, the width of the second metal electrode is greater than the width of the first contact, and the width of the third metal electrode is greater than the width of the fourth contact.

10. The polysilicon resistor of claim 1 , wherein a temperature characteristic of the first polysilicon resistor and a temperature characteristic of the at least one of the second polysilicon resistors are opposite to each other.

11. A reference voltage circuit comprising:

a transistor connected to a power source voltage and supplying a predetermined current; and

a polysilicon resistor generating a reference voltage according to a current flowing to the transistor,

wherein the polysilicon resistor comprises a first polysilicon resistor and at least one of second polysilicon resistors that is coupled to the first polysilicon resistor in series, the first polysilicon resistor and the at least one of the second polysilicon resistors comprise P-type polysilicon, a doping concentration of the first polysilicon resistor is different from a doping concentration of the at least one of the second polysilicon resistors, and the first polysilicon resistor has a region that is not doped with P-type impurities.

12. The reference voltage circuit of claim 11 , wherein a temperature characteristic of the first polysilicon resistor and a temperature characteristic of the at least one of the second polysilicon resistors are opposite to each other.