Field-effect semiconductor device and manufacturing method therefor

• US 9,064,887 B2
• Filed: 09/04/2012
• Issued: 06/23/2015
• Est. Priority Date: 09/04/2012
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Werner, Wolfgang
• Primary Examiner(s): Armand, Marc
• Assistant Examiner(s): BRASFIELD, QUINTON A
• Application Number:
  US13/602,614
• Publication Number:
  US 20140061647A1
• Time in Patent Office: 1,022 Days
• Field of Search: 257/E29.049
• US Class Current: 1/1
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• 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 29/1604 Amorphous materials
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/165 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/267 in different semiconductor regions , e.g. heterojunctions H01L29/263 takes precedence
• CPC Class Codes: H01L 29/66068 the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
• CPC Class Codes: H01L 29/66431 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT with an active layer made of a group 13/15 material H01L29/66462
• 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 29/66893 with a PN junction gate, i.e. JFET
• CPC Class Codes: H01L 29/66909 Vertical transistors, e.g. tecnetrons
• CPC Class Codes: H01L 29/66924 with an active layer made of a group 13/15 material H01L29/66446 takes precedence
• CPC Class Codes: H01L 29/7395 Vertical transistors, e.g. vertical IGBT
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence
• CPC Class Codes: H01L 29/7805 in antiparallel, e.g. freewheel diode
• 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 29/8083 Vertical transistors SIT H01L29/7722
• CPC Class Codes: H01L 29/8611 : Planar PN junction diodes
• CPC Class Codes: H01L 29/872 : Schottky diodes
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

According to an embodiment of a field-effect semiconductor device, the field-effect semiconductor device includes a semiconductor body and a source electrode. The semiconductor body includes a drift region, a gate region and a source region of a first semiconductor material having a first band-gap and an anode region of a second semiconductor material having a second band-gap lower than the first band-gap. The drift region is of a first conductivity type. The gate region forms a pn-junction with the drift region. The source region is of the first conductivity type and in resistive electric connection with the drift region and has a higher maximum doping concentration than the drift region. The anode region is of the second conductivity type, forms a heterojunction with the drift region and is spaced apart from the source region. The source metallization is in resistive electric connection with the source region and the anode region.

Claims

1. A field-effect semiconductor device, comprising:

a semiconductor body of a first band-gap material and having a main surface, the semiconductor body comprising in a cross-section which is substantially vertical to the main surface;

a drift region of a first conductivity type;

a first channel region of the first conductivity type and adjoining the drift region;

a first gate region forming a first pn-junction with the first channel region;

a first body region arranged below the first gate region and forming a second pn-junction with the first channel region such that the first channel region is arranged between the first pn-junction and the second pn-junction; and

a first source region of the first conductivity type, having a higher maximum doping concentration than the first channel region and adjoining the first channel region; and

an anode region of a second band-gap material having a lower band-gap than the first band-gap material, the anode region being of a second conductivity type and forming a heterojunction with the drift region, wherein the heterojunction and the first source region do not overlap when viewed from above.

2. The semiconductor device of claim 1, further comprises in the cross-section at least one of:

a second channel region of the first conductivity type and adjoining the drift region;

a second gate region forming a third pn-junction with the second channel region;

a second body region arranged below the second gate region and forming a fourth pn-junction with the second channel region such that the second channel region is arranged between the third pn-junction and the fourth pn-junction;

a second source region of the first conductivity type having a higher maximum doping concentration than the second channel region and adjoining the second channel region;

a source metallization in ohmic contact with at least one of the anode region, the first source region, the second source region, the first body region and the second body region;

a gate metallization in ohmic contact with at least one of the first gate region and the second gate region; and

a drain metallization arranged opposite to the source metallization and in ohmic contact with the drift region.

3. The semiconductor device of claim 1, wherein the drift region extends to the main surface, and wherein the anode region is arranged above the drift region.

4. The semiconductor device of claim 1, wherein the first band-gap material is selected from the group consisting of GaN, SiC, Si and Si_xGe_1-x.

5. The semiconductor device of claim 1, wherein the second band-gap material is selected from the group consisting of Si and Ge.

6. The semiconductor device of claim 1, wherein the second band-gap material is a non-monocrystalline semiconductor material.

7. The semiconductor device of claim 1, wherein a maximum doping concentration of the anode region is at least three orders of magnitude higher than a maximum doping concentration of the drift region.

8. The semiconductor device of claim 1, wherein the anode region has a maximum doping concentration of at least about 10²⁰ cm⁻

3.

9. A field-effect semiconductor device, comprising:

a semiconductor body of a first band-gap material, having a main surface and comprising in a cross-section which is substantially vertical to the main surface;

a drift region of a first conductivity type and extending to the main surface;

two channel regions of the first conductivity type which are spaced apart by the drift region;

two gate regions of a second conductivity type which are spaced apart by the drift region, each of the two gate regions forming a respective pn-junction with one of the two channel regions;

two body regions arranged vertically below the two gate regions, each of the two body regions forming a further pn-junction with one of the two channel regions; and

two source regions of the first conductivity type, each of the two source regions comprising a higher maximum doping concentration than an adjoining of the two channel regions; and

an anode region of a second band-gap material arranged at the main surface, the second band-gap material having a lower band-gap than the first band-gap material, the anode region being of a second conductivity type and forming a heterojunction with the drift region wherein the heterojunction and the two source regions do not overlap when viewed from above.

10. The semiconductor device of claim 9, wherein the anode region forms the heterojunction only with the drift region.

11. The semiconductor device of claim 9, further comprising in the cross-section at least one of:

a source metallization in ohmic contact with at least one of the anode region, the two source regions, and the two body regions;

a gate metallization in ohmic contact with at least one of the two gate regions; and

a drain metallization arranged opposite to the source metallization and in ohmic contact with the drift region.

12. The semiconductor device of claim 9, wherein the anode region is spaced apart from at least one of the two gate regions, the two body regions and the two source regions when viewed from above.

13. The semiconductor device of claim 9, wherein a maximum doping concentration of the anode region is at least three orders of magnitude higher than a maximum doping concentration of the drift region.

14. The semiconductor device of claim 9, wherein the first band-gap material is a monocrystalline semiconductor material selected from the group consisting of GaN, SiC, Si and Si_xGe_1-x.

15. The semiconductor device of claim 9, wherein the second band-gap material is selected from the group consisting of Si and Ge.

16. The semiconductor device of claim 9, wherein the second band-gap material is a non-monocrystalline semiconductor material.