Semiconductor device

• US 10,056,365 B2
• Filed: 02/23/2015
• Issued: 08/21/2018
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Kueck, Daniel, Elpelt, Rudolf
• Primary Examiner(s): Inoussa, Mouloucoulaye
• Application Number:
  US14/628,721
• Publication Number:
  US 20150171078A1
• Time in Patent Office: 1,275 Days
• Field of Search: 257471, 257472, 257475, 257476, 257480, 257481, 257482, 257485, 257339, 257341, 257342, 257329, 257330, 257331, 257334, 257337
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 29/0615 by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] LDD or drain offset regions H01L29/7833
• CPC Class Codes: H01L 29/0646 PN junctions
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41741 for vertical or pseudo-vertical devices
• CPC Class Codes: H01L 29/41775 characterised by the proximity or the relative position of the source or drain electrode and the gate electrode, e.g. the source or drain electrode separated from the gate electrode by side-walls or spreading around or above the gate electrode
• CPC Class Codes: H01L 29/42316 for field-effect transistors
• CPC Class Codes: H01L 29/8083 Vertical transistors SIT H01L29/7722
• CPC Class Codes: H01L 29/8122 Vertical transistors SIT, PBT H01L29/7722
• CPC Class Codes: H01L 29/8613 Mesa PN junction diodes

Abstract

A semiconductor device incudes a cell region and a contact region, the cell region including a functional unit including a gate electrode, a source and a drain electrode, and the contact region including a gate pad. The gate electrode, the gate pad and the source electrode are disposed on a first main surface of a semiconductor substrate, and the drain electrode is disposed on a second main surface of the semiconductor substrate, the second main surface being opposite to the first main surface. A shielding member is disposed between the gate pad and the drain electrode, the shielding member being electrically connected to the source electrode.

Claims

1. A semiconductor device comprising a transistor in a semiconductor body having a first and a second main surface, the semiconductor body comprising a semiconductor substrate of a second conductivity type and the transistor comprising:

a gate electrode in contact with a semiconductor portion of a first conductivity type;

a source electrode in contact with a semiconductor portion of the second conductivity type;

a drain electrode on the second main surface and electrically connected with a portion of the semiconductor substrate, the source electrode being connected with the portion of the semiconductor substrate by an ohmic contact;

a gate pad laterally separated from the gate electrode and electrically connected to the gate electrode; and

a shielding member comprising a first semiconductor portion of the first conductivity type and a second semiconductor portion of the second conductivity type, the first semiconductor portion being electrically connected to the source electrode via a low-ohmic connection, the second semiconductor portion being disposed over the first semiconductor portion, on a side closer to the first main surface of the semiconductor body, the second semiconductor portion having a doping concentration higher than the doping concentration of the semiconductor substrate, the shielding member being disposed between the gate pad and the drain electrode such that the first semiconductor portion and the second semiconductor portion each horizontally overlap the gate pad.

2. The semiconductor device of claim 1, wherein the semiconductor portion of the first conductivity type in contact with the gate electrode forms a horizontal layer.

3. The semiconductor device of claim 1, wherein the first conductivity type is p type and the second conductivity type is n type.

4. The semiconductor device of claim 1, wherein the first semiconductor portion and the second semiconductor portion of the shielding member form horizontal layers.

5. The semiconductor device of claim 1, wherein the semiconductor substrate is a silicon carbide substrate.

6. A semiconductor device comprising a transistor in a semiconductor body having a first and a second main surface, the semiconductor body comprising a semiconductor substrate of a second conductivity type and the transistor comprising:

a gate electrode in contact with a semiconductor portion of a first conductivity type;

a source electrode in contact with a semiconductor portion of the second conductivity type;

a drain electrode on the second main surface and electrically connected with a portion of the semiconductor substrate, the source electrode being connected with the portion of the semiconductor substrate by an ohmic contact;

a gate pad laterally separated from the gate electrode and electrically connected to the gate electrode; and

a shielding member comprising a first semiconductor portion of the first conductivity type and a second semiconductor portion of the second conductivity type, the first semiconductor portion being in direct contact with a metal layer implementing the source electrode, the shielding member being disposed between the gate pad and the drain electrode such that the first semiconductor portion and the second semiconductor portion each horizontally overlap the gate pad.

7. The semiconductor device of claim 6, wherein the second semiconductor portion is disposed over the first semiconductor portion, on a side closer to the first main surface of the semiconductor substrate.

8. The semiconductor device of claim 6, wherein the semiconductor portion of the first conductivity type in contact with the gate electrode forms a horizontal layer.

9. The semiconductor device of claim 6, wherein the first conductivity type is p type and the second conductivity type is n type.

10. The semiconductor device of claim 6, wherein the semiconductor substrate is a silicon carbide substrate.

11. The semiconductor device of claim 6, wherein the second semiconductor portion of the shielding member has a doping concentration higher than the doping concentration of the semiconductor substrate.

12. The semiconductor device of claim 6, wherein the first semiconductor portion and the second semiconductor portion of the shielding member form horizontal layers.

13. A semiconductor device comprising a transistor in a semiconductor body having a first and a second main surface, the semiconductor body comprising a semiconductor substrate of a second conductivity type and the transistor comprising:

a gate electrode in contact with a semiconductor portion of a first conductivity type;

a source electrode in contact with a semiconductor portion of the second conductivity type;

a drain electrode on the second main surface and electrically connected with a portion of the semiconductor substrate, the source electrode being connected with the semiconductor substrate portion by an ohmic contact;

a gate pad laterally separated from the gate electrode and electrically connected to the gate electrode; and

a shielding member comprising a first semiconductor portion of the first conductivity type and a second semiconductor portion of the second conductivity type, the first semiconductor portion being electrically connected to the source electrode via a low-ohmic connection, the second semiconductor portion being disposed over the first semiconductor portion, on a side closer to the first main surface of the semiconductor body, the shielding member being disposed between the gate pad and the drain electrode such that the first semiconductor portion and the second semiconductor portion each horizontally overlap the gate pad.

14. The semiconductor device of claim 13, wherein the semiconductor portion of the first conductivity type in contact with the gate electrode forms a horizontal layer.

15. The semiconductor device of claim 13, wherein the first conductivity type is p type and the second conductivity type is n type.