Semiconductor component with dynamic behavior

• US 9,202,881 B2
• Filed: 08/05/2008
• Issued: 12/01/2015
• Est. Priority Date: 08/10/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Zundel, Markus, Hirler, Franz
• Primary Examiner(s): Nicely, Joseph C
• Application Number:
  US12/186,034
• Publication Number:
  US 20090039419A1
• Time in Patent Office: 2,674 Days
• Field of Search: 257328-332, 257/335, 257/339, 257/341, 257/342, 257/492, 257/493, 257/E29.118, 257/E29.257, 257/E29.26, 257/E29.262
• US Class Current: 1/1
• CPC Class Codes: H01L 29/0878 Impurity concentration or distribution
• CPC Class Codes: H01L 29/1045 the doping structure being parallel to the channel length, e.g. DMOS like
• 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 29/404 Multiple field plate structures
• 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 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• 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 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7809 having both source and drain contacts on the same surface, i.e. Up-Drain VDMOS transistors
• 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 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence
• CPC Class Codes: H01L 29/861 Diodes

Abstract

One embodiment provides a semiconductor component including a semiconductor body having a first side and a second side and a drift zone; a first semiconductor zone doped complementarily to the drift zone and adjacent to the drift zone in a direction of the first side; a second semiconductor zone of the same conduction type as the drift zone adjacent to the drift zone in a direction of the second side; at least two trenches arranged in the semiconductor body and extending into the semiconductor body and arranged at a distance from one another; and a field electrode arranged in the at least two trenches adjacent to the drift zone. The at least two trenches are arranged at a distance from the second semiconductor zone in the vertical direction, a distance between the trenches and the second semiconductor zone is greater than 1.5 times the mutual distance between the trenches, and a doping concentration of the drift zone in a section between the trenches and the second semiconductor zone differs by at most 35% from a minimum doping concentration in a section between the trenches.

Claims

1. A semiconductor component comprising:

a semiconductor body having a first side and a second side;

a drift zone;

a first semiconductor zone doped complementary to the drift zone and adjacent to the drift zone in a direction of the first side, the first semiconductor zone forming a body zone;

a second semiconductor zone of the same conduction type as the drift zone and adjacent to the drift zone in a direction of the second side, the second semiconductor zone forming a drain zone;

a source zone doped complementary to the body zone and separated from the drift zone by the body zone;

a gate electrode arranged adjacent to the body zone and dielectrically insulated from the body zone by a gate dielectric layer;

at least two trenches arranged in the semiconductor body and extending into the semiconductor body proceeding from the first side in a vertical direction into the drift zone and arranged at a distance from one another in a lateral direction of the semiconductor body;

a field electrode arranged in the at least two trenches adjacent to the drift zone, the field electrode connected to the source zone; and

a field dielectric layer dielectrically insulating the field electrode from the drift zone in a vertical direction and a lateral direction of the semiconductor body and being thicker than the gate dielectric layer,

wherein the at least two trenches are arranged at a distance from the second semiconductor zone in the vertical direction;

wherein a distance between the trenches and the second semiconductor zone is greater than 1.5 times the mutual distance between the trenches, and wherein a doping concentration of the drift zone in a section between the trenches and the second semiconductor zone differs by at most 35% from a minimum doping concentration in a section between the trenches; and

wherein a doping concentration in a section of the drift zone arranged between the trenches is between 5·

10¹⁵ cm³ and 1·

10¹⁷ cm<sup>−

3</sup>.

2. The semiconductor component of claim 1, wherein the doping concentration of the drift zone in a section between the trenches and the second semiconductor zone differs by at most 20% from the minimum doping concentration in the section between the trenches.

3. The semiconductor component of claim 1, wherein the gate electrode and the field electrode are arranged in common trenches.

4. The semiconductor component of claim 1, wherein the drain zone is arranged between the drift zone and a semiconductor layer doped complementarily to the drain zone and which has a connecting zone of the same conduction type as the drain zone, the connecting zone arranged between the first side and the drain zone.

5. The semiconductor component of claim 1, wherein the dimensions and/or the doping concentration of the drift zone are chosen in such a way that when the component is turned off after the occurrence of a voltage breakdown, a depth over which an electric field extends in a direction of the second semiconductor zone proceeding from a semiconductor junction between the drift zone and the first semiconductor zone is dependent on the current flowing through the component, wherein the depth in the case of a current corresponding to a rated current is 1.5 times as large as in the case of a current corresponding to at most a thousandth of the rated current.

6. A method of forming a semiconductor component comprising:

providing a semiconductor body having a first side and a second side;

forming a drift zone;

forming a first semiconductor zone doped complementary to the drift zone and adjacent to the drift zone in a direction of the first side, the first semiconductor zone forming a body zone;

forming a second semiconductor zone of the same conduction type as the drift zone and adjacent to the drift zone in a direction of the second side, the second semiconductor zone forming a drain zone;

forming a source zone doped complementary to the body zone and separated from the drift zone by the body zone;

forming a gate electrode arranged adjacent to the body zone and dielectrically insulated from the body zone by a gate dielectric layer;

arranging at least two trenches in the semiconductor body and extending into the semiconductor body proceeding from the first side in a vertical direction into the drift zone and at a distance from one another in a lateral direction of the semiconductor body;

arranging a field electrode in the at least two trenches adjacent to the drift zone, the field electrode connected to the source zone;

forming a field dielectric layer dielectrically insulating the field electrode from the drift zone in a vertical direction and a lateral direction of the semiconductor body and being thicker than the gate dielectric layer;

arranging the at least two trenches at a distance from the second semiconductor zone in the vertical direction;

arranging the trenches and the second semiconductor zone such that a distance between them is greater than 1.5 times the mutual distance between the trenches;

providing a doping concentration of the drift zone in a section between the trenches and in the second semiconductor zone such that they differ by at most 35% from a minimum doping concentration in a section between the trenches; and

providing a doping concentration between 5·

10¹⁵ cm<sup>−

3</sup> and 1·

10¹⁷ cm<sup>−

3</sup> in the section of the drift zone between the trenches.

7. The method of claim 6, wherein the doping concentration of the drift zone in a section between the trenches and the second semiconductor zone differs by at most 20% from the minimum doping concentration in the section between the trenches.

8. The method of claim 6, wherein a distance between the trenches and the second semiconductor zone and a doping concentration of the drift zone in the section between the trenches and the second semiconductor zone are coordinated with one another in such a way that an integral of the doping concentration of the drift zone in a vertical direction of the semiconductor body between the trenches and the second semiconductor zone is greater than or equal to 1.5 times the breakdown charge of the semiconductor material of the drift zone.

9. The method of claim 8, wherein the integral of the dopant charge of the drift zone is greater than or equal to 2 times the breakdown charge of the semiconductor material of the drift zone.

10. The method of claim 9, wherein the integral of the dopant charge of the drift zone is greater than or equal to 2.5 times the breakdown charge of the semiconductor material of the drift zone.