SOI DEVICE AND METHOD FOR ITS FABRICATION

• US 20100187586A1
• Filed: 03/18/2010
• Published: 07/29/2010
• Est. Priority Date: 07/21/2006
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: GlobalFoundries, Inc.
• Inventors: PELLELA, Mario M., WU, Donggang D., BULLER, James F.
• Granted Patent: US 7,915,658 B2
• Time in Patent Office: Days
• US Class Current: 257/300
• CPC Class Codes: H01L 21/743 Making of internal connections, substrate contacts
• CPC Class Codes: H01L 21/84 the substrate being other than a semiconductor body, e.g. being an insulating body
• CPC Class Codes: H01L 27/0255 using diodes as protective elements
• CPC Class Codes: H01L 27/1203 the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688

Abstract

A silicon on insulator (SOI) device is provided. The device includes an MOS capacitor coupled between voltage busses and formed in a monocrystalline semiconductor layer overlying an insulator layer and a semiconductor substrate. The device includes at least one electrical discharge path for discharging potentially harmful charge build up on the MOS capacitor. The MOS capacitor has a conductive electrode material forming a first plate of the MOS capacitor and an impurity doped region in the monocrystalline silicon layer beneath the conductive electrode material forming a second plate. A first voltage bus is coupled to the first plate of the capacitor and to an electrical discharge path through a diode formed in the semiconductor substrate and a second voltage bus is coupled to the second plate of the capacitor.

Claims

1. A semiconductor on insulator (SOI) device, comprising:

a semiconductor substrate including a pn junction diode formed in a first portion of the semiconductor substrate;

a buried insulator layer overlying the semiconductor substrate;

a monocrystalline semiconductor layer overlying the buried insulator layer;

an MOS capacitor comprising;

a first plate that comprises gate electrode forming material having a first conductivity type;

a second plate that comprises an impurity doped region having the first conductivity type in the monocrystalline semiconductor layer beneath the gate electrode forming material; and

a dielectric layer disposed between the first plate and the second plate;

a first voltage bus coupled to the pn junction diode and the first plate; and

a second voltage bus coupled to the second plate such that the MOS capacitor is coupled between the first voltage bus and the second voltage bus.

2. The semiconductor on insulator (SOI) device of claim 1, wherein the pn junction diode comprises an n-type impurity doped region, and wherein the first voltage bus is coupled to the n-type impurity doped region.

3. The semiconductor on insulator (SOI) device of claim 1, further comprising:

a first electrical discharge path coupling the first plate to the pn junction diode, wherein the first electrical discharge path includes the first voltage bus.

4. The semiconductor on insulator (SOI) device of claim 3, further comprising:

a second electrical discharge path coupling the second plate to the semiconductor substrate, wherein the second electrical discharge path includes the second voltage bus.

5. The semiconductor on insulator (SOI) device of claim 4, wherein the second electrical discharge path comprises conductors without any intermediate device included in the second electrical discharge path.

6. The semiconductor on insulator (SOI) device of claim 1, further comprising:

a first electrical contact region formed in a second portion of the semiconductor substrate, wherein the second voltage bus is coupled to the first electrical contact region.

7. The semiconductor on insulator (SOI) device of claim 1, wherein the MOS capacitor further comprises:

a first contact region coupled to the second voltage bus and electrically in series with the impurity doped region, and a second contact region coupled to the second voltage bus and electrically in series with the impurity doped region.

8. The semiconductor on insulator (SOI) device of claim 7, wherein the first contact region and the second contact region each have the first conductivity type.

9. The semiconductor on insulator (SOI) device of claim 7, wherein the first conductivity type is n-type.

10. The semiconductor on insulator (SOI) device of claim 1 further comprising:

a PMOS transistor formed in a first electrically isolated portion of the monocrystalline semiconductor layer;

an NMOS transistor formed in a second electrically isolated portion of the monocrystalline semiconductor layer; and

wherein the MOS capacitor is formed in a third electrically isolated portion of the monocrystalline semiconductor layer.

11. The semiconductor on insulator (SOI) device of claim 10, wherein a drain of the PMOS transistor is coupled to the second voltage bus and a drain of the NMOS transistor is coupled to the first voltage bus.

12. A semiconductor on insulator (SOI) device comprising a p-type semiconductor substrate, a buried insulator layer overlying the p-type semiconductor substrate, and a monocrystalline semiconductor layer overlying the buried insulator layer, the SOI device further comprising:

a pn junction diode formed in a first portion of the p-type semiconductor substrate, wherein the first portion is doped with n-type impurities to form an n-type region;

a contact in a second portion of the p-type semiconductor substrate that is doped with p-type impurities;

a capacitor, comprising;

a first plate comprising an n-type impurity doped region in a portion of the monocrystalline semiconductor layer, an insulator layer overlying the portion of the monocrystalline semiconductor layer, and a second plate comprising a conductive electrode overlying the insulator layer;

a first bus coupled to the second plate and to the n-type region of the pn junction diode; and

a second bus coupled to the first plate and to the contact in the second portion of the p-type semiconductor substrate.

13. The semiconductor on insulator (SOI) device of claim 12, wherein the capacitor further comprises:

a first contact region electrically in series with the impurity doped region, and a second contact region electrically in series with the impurity doped region.

14. The semiconductor on insulator (SOI) device of claim 13, wherein the conductive electrode, the first contact region, and the second contact region each have n-type conductivity.

15. The semiconductor on insulator (SOI) device of claim 12, further comprising:

a first electrical discharge path coupling the first plate to the contact in the second portion of the p-type semiconductor substrate; and

a second electrical discharge path coupling the second plate to the n-type region of the pn junction diode, wherein the second electrical discharge path comprises conductors without any intermediate device included in the second electrical discharge path.

16. The semiconductor on insulator (SOI) device of claim 12, wherein the conductive electrode comprises a first portion of a polycrystalline silicon layer overlying the insulator layer, and further comprising:

an NMOS transistor comprising a first gate electrode, the first gate electrode comprising a second portion of the polycrystalline silicon layer; and

a PMOS transistor comprising a second gate electrode, the second gate electrode comprising a third portion of the polycrystalline silicon layer.

17. A semiconductor component, comprising:

a semiconductor on insulator (SOI) substrate having a first p-type semiconductor layer having a contact area, a layer of insulator on the first p-type semiconductor layer, and a second semiconductor layer overlying the layer of insulator;

an MOS transistor comprising an n-type drain region formed in the second semiconductor layer;

a pn junction diode comprising an n-type impurity doped region formed in the first p-type semiconductor layer;

a capacitor comprising;

a bottom capacitor plate comprising an n-type region in the second semiconductor layer, a first n-type contact region electrically in series with the n-type region, a second n-type contact region electrically in series with the n-type region, a capacitor dielectric layer overlying the n-type region in the second semiconductor layer, and a top capacitor plate overlying the capacitor dielectric layer;

a first voltage bus coupled to the n-type impurity doped region and to the top capacitor plate;

a first electrical discharge path coupling the top capacitor plate to the pn junction diode;

a second voltage bus coupled to the contact area in the first p-type semiconductor layer, to the n-type region in the second semiconductor layer and to the n-type drain region in the second semiconductor layer; and

a second electrical discharge path coupling the bottom capacitor plate to the contact area.

18. The semiconductor component of claim 17, wherein the first voltage bus and the second voltage bus comprise a first layer of metal, and further comprising:

a first interconnect electrically coupled to a portion of the n-type drain region and to the second voltage bus, the first interconnect comprising a second layer of metal different that the first layer of metal; and

a second interconnect electrically coupled to a portion of the n-type impurity doped region and to the first voltage bus, the second interconnect comprising the second layer of metal.