SGT MOSFET WITH ADJUSTABLE CRSS AND CISS

• US 20190027596A1
• Filed: 07/29/2018
• Published: 01/24/2019
• Est. Priority Date: 12/02/2015
• Status: Active Grant

• Current Assignee: Hunteck Semiconductor (Shanghai), Ltd.
• Original Assignee: Hunteck Semiconductor (Shanghai), Ltd.
• Inventors: HU, Jun, LUO, Zhiyun, Wang, Fei, Pan, Mengyu
• Granted Patent: US 10,923,588 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 21/32139 using masks
• 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 29/401 Multistep manufacturing processes
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/42372 characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out H01L29/42324 takes precedence
• 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 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A semiconductor power device includes a plurality of power transistor cells each having a trenched gate disposed in a gate trench opened in a semiconductor substrate wherein a plurality of the trenched gates further include a shielded bottom electrode disposed in a bottom portion of the gate trench electrically insulated from a top gate electrode disposed at a top portion of the gate trench by an inter-electrode insulation layer. At least one of the shielded bottom electrode is connected a source metal and at least one of the top electrodes in the gate trench is connected to a source metal of the power device.

Claims

1. A method for manufacturing a power device in a semiconductor substrate comprising:

opening a plurality of trenches and filling the trenches with a conductive gate material;

applying a mask for carrying out a time etch for etching back the conductive gate material from a set of selected trenches thus leaving a bottom portion of the gate conductive material in the selected trenches;

covering the bottom portion in the selected trenches with a shielding insulation layer to form a bottom shielded electrode followed by filling the selected trench with the conductive gate material to form top electrodes on top of the shielding insulation layer; and

wherein the step of forming the plurality of trenches further includes a step form a source runner trench and a gate runner trench extending laterally between an active area and a termination area and further including a step of filling the source runner trench with the conductive gate material to electrically connect at least one of the bottom shielded electrodes to a source metal of the power device.

2. The method of claim 1 further comprising:

filling the source runner trench with the conductive gate material to electrically connect at least one of the top electrodes to the source metal of the power device.

3. The method of claim 1 further comprising:

filling the gate runner trench with the conductive gate material to electrically connect at least one of the shielded bottom electrodes to a gate pad of the power device.

4. The method of claim 1 further comprising:

filling the gate runner trench with the conductive gate material to electrically connect at least one of the top electrodes to a gate pad of the power device.

5. The method of claim 1 further comprising:

implanting a body dopant followed by implanting a source dopant to form body regions and source regions near a top surface of the power device; and

covering the top surface with an insulation layer followed by opening a plurality of source/body contact trenches and gate contact trenches through the insulation layer followed by filling the source/body contact trenches and the gate contact trenches with a contact metal; and

depositing a metal layer over the insulation layer and patterning the metal layer into a source metal for contacting the source/body contact trenches on top of the active area and the source runner for contacting the body and source regions and further patterning the metal layer into a gate pad for contacting the gate contact trenches on top of the gate runners for contacting the top electrodes.

6. The method of claim 5 wherein:

the step of applying a mask for carrying out the time etch for etching back the conductive gate material from a set of selected trenches further comprising a step of covering at least a covered trench for keeping the conductive gate material in the covered trench; and

the step of opening a plurality of source/body contact trenches further includes a step of opening'"'"'a source/body contact trenches directly on top of the covered trench to electrically connected to the source metal in the active area.

7. The method of claim 6 wherein:

the step of filling the source runner trench with the conductive gate material further comprising a step of filling the source runner trenches with the conductive gate material to electrically connect a plurality of the bottom shielded electrodes to a source metal of the power device.

8. The method of claim 6 wherein:

the step of filling the gate runner trench with the conductive gate material further comprising a step of filling the gate runner trenches with the conductive gate material to electrically connect a plurality of the top electrodes to the gate pad of the power device.

9. The method of claim 5 wherein:

the step of opening a plurality of source/body contact trenches further includes a step of opening a source/body contact trench directly on top of one of the selected trenches to electrically connect a top electrode in one of the selected trenches to the source metal.

10. The method of claim 5 wherein:

the step of applying a mask for carrying out the time etch for etching back the conductive gate material from a set of selected trenches further comprising a step of covering at least a covered trench for keeping the conductive gate material in the covered trench; and

the step of opening a plurality of gate contact trenches further includes a step of opening a gate contact trench directly on top of the covered trench to electrically connect the conductive material in the covered trench to the gate pad.