Semiconductor Device with Field Electrode Structure

• US 20160079376A1
• Filed: 08/28/2015
• Published: 03/17/2016
• Est. Priority Date: 09/17/2014
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Hirler, Franz, Blank, Oliver, Siemieniec, Ralf
• Granted Patent: US 9,722,036 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 29/0623 Buried supplementary region, e.g. buried guard ring multi-RESURF H01L29/0634
• CPC Class Codes: H01L 29/0692 Surface layout
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41758 for lateral devices with structured layout for source or drain region, i.e. the source or drain region having cellular, interdigitated or ring structure or being curved or angular H01L29/41733 - H01L29/4175 take precedence
• CPC Class Codes: H01L 29/41766 with at least part of the source or drain electrode having contact below the semiconductor surface, e.g. the source or drain electrode formed at least partially in a groove or with inclusions of conductor inside the semiconductor H01L29/41733 - H01L29/41758 take precedence
• CPC Class Codes: H01L 29/7396 with a non planar surface, e.g. with a non planar gate or with a trench or recess or pillar in the surface of the emitter, base or collector region for improving current density or short circuiting the emitter and base regions H01L29/7398 takes precedence
• 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 29/7806 the other device being a Schottky barrier diode
• 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 29/8613 Mesa PN junction diodes
• CPC Class Codes: H01L 29/872 Schottky diodes
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 3/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: H02M 7/5387 : in a bridge configuration
• CPC Class Codes: Y02B 70/10 : Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

According to an embodiment a semiconductor device includes a semiconductor body with a mesa section that may include a rectifying structure and a first drift zone section. The mesa section surrounds a field electrode structure that includes a field electrode and a field dielectric sandwiched between the field electrode and the semiconductor body. A maximum horizontal extension of the field electrode in a measure plane parallel to a first surface of the semiconductor body is at most 500 nm.

Claims

1. A semiconductor device comprising:

a semiconductor body comprising a mesa section that comprises a rectifying structure and a first drift zone section;

a field electrode structure surrounded by the mesa section and comprising a field electrode and a field dielectric sandwiched between the field electrode and the semiconductor body, wherein an extension of the field electrode in a plane approximately parallel to a first surface of the semiconductor body is less than approximately 500 nm.

2. The semiconductor device of claim 1, wherein the rectifying structure is a pn junction or a Schottky diode.

3. The semiconductor device of claim 1, wherein the rectifying structure comprises a body zone separating a source zone and the first drift zone section, the body zone forming a first pn junction with the source zone and a second pn junction with the first drift zone section.

4. The semiconductor device of claim 3, further comprising a gate structure surrounding the field electrode structure and comprising a gate electrode and a gate dielectric separating the gate electrode and the body zone.

5. The semiconductor device of claim 1, wherein the mesa section is sandwiched between the field electrode structure and a gate structure.

6. The semiconductor device of claim 1, wherein gate electrodes of a plurality of transistor cells form a grid embedding mesa sections of the plurality of transistor cells.

7. The semiconductor device of claim 1, wherein a gate structure is sandwiched between the field electrode structure and the mesa section.

8. The semiconductor device of claim 7, wherein mesa sections of a plurality of transistor cells form a grid embedding the gate structures and field electrode structures of the transistor cells.

9. The semiconductor device of claim 3, further comprising stripe-shaped gate structures extending between lines of field electrode structures, respectively and comprising a gate electrode and a gate dielectric separating the gate electrode and the body zones.

10. The semiconductor device of claim 1, wherein a first horizontal extension of the field electrode approximately parallel to the first surface of the semiconductor body is at most twice as large as a second horizontal extension approximately orthogonal to the first horizontal extension.

11. The semiconductor device of claim 1, wherein a horizontal cross-sectional area of the field electrode approximately parallel to the first surface of the semiconductor body is a square with rounded corners or a hexagon with rounded corners.

12. The semiconductor device of claim 1, wherein a vertical cross-sectional shape of a buried end portion of the field electrode structure approximately orthogonal to the first surface of the semiconductor body is devoid of a straight section parallel to the first surface.

13. An electronic assembly, comprising:

a semiconductor device that comprises a semiconductor body comprising a mesa section that comprises a rectifying structure and a first drift zone section;

a field electrode structure surrounded by the mesa section and comprising a field electrode and a field dielectric sandwiched between the field electrode and the semiconductor body, wherein an extension of the field electrode in a plane approximately parallel to a first surface of the semiconductor body is less than approximately 500 mm.

14. The electronic assembly of claim 13, wherein the electronic assembly is selected from a group comprising a motor drive, a switched mode power supply, a primary stage of a switched mode power supply, a synchronous rectifier, a primary stage of a DC-to-AC converter, a secondary stage of a DC-to-AC converter, a primary stage of a DC-to-DC converter and a solar power converter.

15. The electronic assembly of claim 13, wherein the rectifying structure comprises a body zone separating a source zone and the first drift zone section, the body zone forming a first pn junction with the source zone and a second pn junction with the first drift zone section.

16. A semiconductor device, comprising:

a semiconductor body comprising mesa sections, each mesa section comprising a rectifying structure and a first drift zone section;

an at least in segments stripe-shaped field electrode structure sandwiched between two of the mesa sections and comprising a field electrode and a field dielectric sandwiched between the field electrode and the semiconductor body, wherein a width of the field electrode in a plane approximately parallel to a first surface of the semiconductor body is less than approximately 100 nm.

17. The semiconductor device of claim 16, wherein the rectifying structure comprises a body zone separating a source zone and the first drift zone section, the body zone forming a first pn junction with the source zone and a second pn junction with the first drift zone section.

18. The semiconductor device of claim 16, wherein the mesa sections are sandwiched between respective field electrode structures and respective gate structures.

19. The semiconductor device of claim 16, wherein a horizontal width of the stripe-shaped field electrode structures in the plane approximately parallel to the first surface of the semiconductor body is less than approximately 50 nm.

20. The semiconductor device of claim 16, wherein, in the plane approximately parallel to the first surface of the semiconductor body, a ratio between a cross-sectional area of the field electrode and a total cross-sectional area of a transistor cell comprising the field electrode structure is less than approximately 0.1 in a cell area.