Double gate transistor device and method of operating

• US 10,276,681 B2
• Filed: 02/29/2016
• Issued: 04/30/2019
• Est. Priority Date: 02/29/2016
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Bina, Markus, Mauder, Anton, Barrenscheen, Jens
• Primary Examiner(s): Chen, Patrick C
• Application Number:
  US15/056,392
• Publication Number:
  US 20170250260A1
• Time in Patent Office: 1,156 Days
• Field of Search: 327109
• CPC Class Codes: H01L 29/0878 Impurity concentration or distribution
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/4238 characterised by the surface lay-out
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/7831 with multiple gate structure FinFETs or MuGFETs H01L29/7855, thin film transistors H01L29/78645
• CPC Class Codes: H03K 17/163 Soft switching
• CPC Class Codes: H03K 17/567 Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT
• CPC Class Codes: H03K 17/687 the devices being field-effect transistors

Abstract

In accordance with an embodiment, a method include switching on a transistor device by generating a first conducting channel in a body region by driving a first gate electrode and, before generating the first conducting channel, generating a second conducting channel in the body region by driving a second gate electrode. The first gate electrode is dielectrically insulated from a body region by a first gate dielectric, and the second gate electrode is dielectrically insulated from the body region by a second gate dielectric, arranged adjacent the first gate electrode, and separated from the first gate electrode by a separation layer. The body region is arranged between a source region and a drift region, and wherein the drift region is arranged between body region and a drain region.

Claims

1. A method comprising:

switching on a transistor device by generating a first conducting channel in a body region by driving a first gate electrode and, before generating the first conducting channel, generating a second conducting channel in the body region by driving a second gate electrode,

wherein the first gate electrode is dielectrically insulated from the body region by a first gate dielectric,

wherein the second gate electrode is dielectrically insulated from the body region by a second gate dielectric, arranged adjacent the first gate electrode, and separated from the first gate electrode by a separation layer,

wherein the body region is arranged between a source region and a drift region, and wherein the drift region is arranged between the body region and a drain region,

wherein driving the first gate electrode comprises increasing a first drive voltage between the first gate electrode and the source region from a first off-level to a first on-level,

wherein driving the second gate electrode comprises increasing a second drive voltage between the second gate electrode and the source region from a second off-level to a second on-level, and

wherein the second off-level is different from the first off-level.

2. The method of claim 1, wherein driving the first gate electrode comprises clamping the second gate electrode to the second on-level.

3. The method of claim 1, wherein driving the first gate electrode and the second gate electrode comprises increasing the second drive voltage faster than the first drive voltage.

4. The method of claim 1, further comprising:

detecting a change in an operation state of the transistor device,

wherein detecting the operation state comprises monitoring at least one electrical parameter of the second gate electrode.

5. The method of claim 4, wherein monitoring the at least one electrical parameter of the second gate electrode comprises monitoring at least one of an electrical potential and a current to or from the second gate electrode.

6. The method of claim 5, wherein monitoring the at least one electrical parameter comprises:

filtering a signal representing the current to or from the second gate electrode to generate a filter signal; and

comparing the filter signal with a threshold.

7. The method of claim 6, wherein detecting the change of the operation state comprises detecting the change in the operation state if the filter signal reaches the threshold.

8. The method of claim 4, wherein driving the first gate electrode further comprises driving the first gate electrode based on a detected change of the operation state.

9. The method of claim 8, wherein driving the first gate electrode based on the detected change of the operation state comprises:

driving the first gate electrode in accordance with a first drive parameter before the change of the operation state has been detected; and

driving the first gate electrode in accordance with a second drive parameter different from the first drive parameter after the change of the operation state has been detected.

10. The method of claim 9, wherein the first drive parameter comprises a first current level of a drive current into the first gate electrode and the second drive parameter comprises a second current level of the drive current higher than the first current level.

11. The method of claim 1, further comprising switching off the transistor device by interrupting the first conducting channel in the body region by driving the first gate electrode to a first off voltage, and, after interrupting the first conducting channel, interrupting the second conducting channel in the body region by driving the second gate electrode to a second off voltage.

12. The method of claim 1, wherein the second gate electrode is positioned closer to the drift region of the transistor device than the first gate electrode.

13. A method, comprising:

driving a first gate electrode of a transistor device and monitoring at least one electrical parameter of a second gate electrode of the transistor device,

wherein the first gate electrode is dielectrically insulated from a body region by a first gate dielectric,

wherein the second gate electrode is dielectrically insulated from the body region by a second gate dielectric, arranged adjacent the first gate electrode, and separated from the first gate electrode by a separation layer,

wherein the body region is arranged between a source region and a drift region, and wherein the drift region is arranged between the body region and a drain region, and

wherein monitoring the at least one electrical parameter of the second gate electrode comprises measuring a current flowing to the second gate electrode,

wherein driving the first gate electrode comprises increasing a first drive voltage between the first gate electrode and the source region from a first off-level to a first on-level,

wherein driving the second gate electrode comprises increasing a second drive voltage between the second gate electrode and the source region from a second off-level to a second on-level, and

wherein the second off-level is different from the first off-level.

14. The method of claim 13, further comprising driving the second gate electrode of the transistor device at the same time as driving the first gate electrode.

15. The method of claim 13, wherein driving the first gate electrode comprises increasing a voltage of the first gate electrode according to a first slope, and driving the second gate electrode comprises increasing a voltage of the second gate electrode according to a second slope faster than the first slope.

16. The method of claim 15, further comprising determining when the transistor device turns on based on measuring the current.

17. The method of claim 15, further comprising filtering the measured second current prior to determining when the transistor device turns on.

18. The method of claim 17, wherein filtering the measured current comprises integrated the measured current to determine a change of electrical charge stored in the second gate electrode.

19. The method of claim 17, wherein filtering the measured current comprises differentiating the measured current to determine a rapid increase or decrease of a current flowing to or from the second gate electrode.

20. A method comprising:

switching on a transistor device by generating a first conducting channel in a body region by driving a first gate electrode and, before generating the first conducting channel, generating a second conducting channel in the body region by driving a second gate electrode,

wherein the first gate electrode is dielectrically insulated from the body region by a first gate dielectric,

wherein the second gate electrode is dielectrically insulated from the body region by a second gate dielectric, arranged adjacent the first gate electrode, and separated from the first gate electrode by a separation layer,

wherein the body region is arranged between a source region and a drift region, and wherein the drift region is arranged between the body region and a drain region,

wherein driving the first gate electrode comprises increasing a first drive voltage between the first gate electrode and the source region from a first off-level to a first on-level according to a first slope, and

wherein driving the second gate electrode comprises increasing a second drive voltage between the second gate electrode and the source region from a second off-level to a second on-level according to a second slope, wherein the second slope is greater than the first slope, and

wherein the second off-level is different from the first off-level.