MOS field plate trench transistor device

• US 7,372,103 B2
• Filed: 03/31/2006
• Issued: 05/13/2008
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Hirler, Franz, Zundel, Markus
• Primary Examiner(s): QUACH, TUAN N
• Application Number:
  US11/395,103
• Publication Number:
  US 20060258105A1
• Time in Patent Office: 774 Days
• Field of Search: 257/327, 257/328, 257/330, 257/409, 257/E29.009
• US Class Current: 257/330
• CPC Class Codes: H01L 29/0873 Drain regions
• 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 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A MOS field plate trench transistor device is disclosed. In one embodiment, in order to obtain a lowest possible on resistance, in the case of a MOS field plate trench transistor device having a body contact hole, it is proposed to form the avalanche breakdown region preferably in an end region of a provided trench structure by virtue of the fact that a mesa region with the body contact region in the semiconductor region as intermediate region in a direction running perpendicular to the first direction and with respect to an adjacent MOS transistor device has a width D_Mesa, the value of which corresponds to the value of the width D_Trench of the trench structure in this direction or exceeds said value and does not go beyond 1.5 times said value, so that the following holds true: D_Trench≦D_Mesa≦1.5·D_Trench. As an alternative, the width D_Mesa is chosen such that the body contact hole precisely still has space, but the breakdown region is in any event shifted into the end region.

Claims

1. A MOS field plate trench transistor device having a trench structure extending in a first direction in a semiconductor region comprising:

a source region and a drain region formed in the semiconductor region with a first conductivity type and, between the source region and the drain region, a body region is formed with a second conductivity type, which is opposite to the first conductivity type;

a gate electrode device formed in between in the interior of the trench structure in a manner insulated by an insulation region; and

a mesa region is located in the semiconductor region as intermediate region in a direction running perpendicular to the first direction and with respect to an adjacent MOS transistor device has a width D_Mesa, the value of which corresponds to the value of the width D_Trench of the trench structure in this direction or exceeds said value and does not go beyond 1.5 times said value, so that the following holds true;

D_Trench≦

D_Mesa≦

1.5·

D_Trench′

where D_Mesa is the average value of the width of the mesa region at the level of the pn junction between the body region and the drain region and the width of the mesa region at 80% of the depth of the trench structure and

in which the mesa region is provided with a contact hole to the body region.

2. The MOS field plate trench transistor device of claim 1, wherein the avalanche breakdown region of the MO S transistor device is formed in a lower region of the trench structure.

3. The MOS field plate trench transistor device of claim 1, comprising wherein the width D_Mesa and the width D_Trench are in the following relationship with respect to the maximum thickness D_FOX of the insulation region:

2.5·

D_FOX<

D_Trench≦

D_Mesa≦

7.5·

D_FOX·

4. The MOS field plate trench transistor device of claim 1, comprising wherein the contact hole is formed globally along the trench structure.

5. The MOS field plate trench transistor device of claim 1, comprising wherein a body reinforcement region is formed locally in regions of the contact hole.

6. A MOS field plate trench transistor device having a trench structure extending in a first direction in a semiconductor region, comprising:

a source region and a drain region formed in the semiconductor region with a first conductivity type and, between the source region and the drain region, a body region is formed with a second conductivity type, which is opposite to the first conductivity type;

a gate electrode device is formed in between in the interior of the trench structure in a manner insulated by an insulation region;

a mesa region having a width D_Mesa in the semiconductor region as intermediate region in a direction running perpendicular to the first direction and with respect to an adjacent MOS transistor device has a width D_Mesa; and

wherein the mesa region is provided with a contact hole to the body region, wherein the width D_Mesa is chosen such that, it is reduced to such a great extent that an avalanche breakdown occurs in the bottom region of the trench structure, and that it is reduced only to an extent such that the contact hole still has space.

7. The MOS field plate trench transistor device of claim 6, comprising wherein the width D_Mesa and the width D_Trench are in the following relationship with respect to the maximum thickness D_FOX of the insulation region:

2.5·

D_FOX<

D_Trench≦

D_Mesa≦

7.5·

D_FOX·

8. The MOS field plate trench transistor device of claim 6, comprising wherein the contact hole is formed globally along the trench structure.

9. The MOS field plate trench transistor device of claim 6, comprising wherein a body reinforcement region is formed locally in regions of the contact hole.

10. The MOS field plate trench transistor device of claim 6, comprising wherein the body region is formed such that it is reinforced toward the drain region with a body reinforcement region of the second conductivity type.

11. The MOS field plate trench transistor device of claim 6, comprising wherein the avalanche breakdown region of the MOS transistor device is formed by a region of maximum electric field strength.

12. The MOS field plate trench transistor device of claim 11, comprising wherein the region of maximum electric field strength is formed between the source region and the drain region in direct proximity to the insulation region and to the end region or to the lower region of the trench structure in a manner facing away from the gate electrode device.

13. The MOS field plate trench transistor device of claim 11, comprising wherein the region of maximum electric field strength is formed between the source region and the drain region in direct proximity to the end region or to the lower region of the trench structure and in a manner facing away from the gate electrode device in the region of a space charge zone, which is formed when a breakdown voltage is present between a provided body region or body reinforcement region and the drain region, in a half thereof which faces the drain region.

14. The MOS field plate trench transistor device of claim 6, comprising wherein the trench structure is formed such that it reaches approximately as far as a first semiconductor subregion of the semiconductor region or into the semiconductor subregion.

15. The MOS field plate trench transistor device of claim 6, comprising wherein the semiconductor region has a field buffer zone.

16. The MOS field plate trench transistor device of claim 15, comprising wherein the field buffer zone is formed between a first semiconductor subregion and a second semiconductor subregion.

17. The MOS field plate trench transistor device of claim 15, comprising wherein the trench structure is formed such that it reaches approximately as far as the field buffer zone or into the field buffer zone.

18. The MOS field plate trench transistor device of claim 6, comprising wherein the gate electrode device comprises a plurality of electrodes.

19. The MOS field plate trench transistor of claim 18, comprising wherein the plurality of electrodes are at a plurality of different potentials.

20. The MOS field plate trench transistor device of claim 19, comprising

wherein the different potentials are gate potential and source potential.

21. The MOS field plate trench transistor device of claim 6, comprising wherein at least one local dopant maximum of the first conductivity type is formed in the zone between body region and drain region.

22. The MOS field plate trench transistor device of claim 6, comprising wherein the drain region or the connection region therefor, whilst avoiding to the greatest possible extent a rear-side contact-connection of the semiconductor region, is formed on the same side of the semiconductor region as the source region or the connection region therefor.

23. A MOS field plate trench transistor device having a trench structure extending in a first direction in a semiconductor region comprising:

a source region and a drain region formed in the semiconductor region with a first conductivity type and, between the source region and the drain region, a body region is formed with a second conductivity type, which is opposite to the first conductivity type;

a gate electrode device formed in between in the interior of the trench structure in a manner insulated by an insulation region; and

means for providing a mesa region is located in the semiconductor region as intermediate region in a direction running perpendicular to the first direction and with respect to an adjacent MOS transistor device has a width D_Mesa, the value of which corresponds to the value of the width D_Trench of the trench structure in this direction or exceeds said value and does not go beyond 1.5 times said value, so that the following holds true;

D_Trench≦

D_Mesa≦

1.5·

D_Trench′

where D_Mesa is the average value of the width of the mesa region means at the level of the pn junction between the body region and the drain region and the width of the mesa region at 80% of the depth of the trench structure and in which the mesa region is provided with a contact hole to the body region.