Device structure and manufacturing method using HDP deposited source-body implant block

• US 8,035,159 B2
• Filed: 04/30/2007
• Issued: 10/11/2011
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: Alpha & Omega Semiconductor, Ltd.
• Original Assignee: Alpha & Omega Semiconductor, Ltd.
• Inventors: Bhalla, Anup, Tai, Sung-Shan, Hébert, François, Lui, Sik K
• Primary Examiner(s): Matthews; Colleen
• Assistant Examiner(s): Yushina; Galina
• Application Number:
  US11/796,985
• Publication Number:
  US 20080265289A1
• Time in Patent Office: 1,625 Days
• Field of Search: 257/77, 257/409, 257/471, 257/342, 257/365, 257/328, 257/341, 257/287, 257/401, 257/E29.201, 257330-332, 257/334, 257/E21.04, 257/E21.42
• US Class Current: 257/330
• 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 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• 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 29/7806 the other device being a Schottky barrier diode
• 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

This invention discloses a semiconductor power device. The trenched semiconductor power device includes a trenched gate, opened from a top surface of a semiconductor substrate, surrounded by a source region encompassed in a body region near the top surface above a drain region disposed on a bottom surface of a substrate. The semiconductor power device further includes an implanting-ion block disposed above the top surface on a mesa area next to the body region having a thickness substantially larger than 0.3 micron for blocking body implanting ions and source ions from entering into the substrate under the mesa area whereby masks for manufacturing the semiconductor power device can be reduced.

Claims

1. A semiconductor power device comprising a trenched gate, opened from a top surface of a semiconductor substrate, surrounded by a source region encompassed in a body region near said top surface above a drain region disposed on a bottom surface of a said substrate, wherein said semiconductor power device further comprising:

an implanting-ion block disposed above said top surface on a mesa area above said body region and in a middle portion between two of said trenched gates having a thickness for blocking body implanting ions from entering into said substrate under said mesa area whereby masks for manufacturing said semiconductor power device can be reduced;

said body region constituting a merged body region merged from two separated body regions between two of said trenched gates having an inverted V pinnacle point near a bottom center of said body region between two of said trenched gates; and

a bottom portion of said trenched gate is filled with a trench bottom block formed simultaneously with said implanting ion block by filling trenches of said trenched gates with a layer of said implanting ion block wherein said trench bottom block filled in said bottom portion of said trenched gate having a thickness from a bottom of said trenched gate substantially equal to an etch-down thickness in etching and removing said layer of said implanting ion-block from a top portion of said trenched gate and from peripheral areas surrounding a top surface of said trenched gate while leaving said implanting-ion block as an intact portion of said layer of said implanting ion block.

2. The power semiconductor power device of claim 1 wherein:

said implanting-ion block and said trench bottom block further comprising an oxide layer.

3. The power semiconductor power device of claim 1 wherein:

said implanting-ion block and said trench bottom block further comprising a chemical vapor deposited (CVD) oxide layer.

4. The power semiconductor power device of claim 1 wherein:

said implanting-ion block and said trench bottom block further comprising a thermal oxide layer.

5. The power semiconductor power device of claim 1 wherein:

said implanting-ion block and said trench bottom block further comprising a high-density plasma (HDP) oxide layer.

6. The power semiconductor power device of claim 1 wherein:

said trench bottom block and said implanting ion block further comprising a high-density plasma (HDP) deposited thick oxide layer and said trench bottom block having a thickness greater than a gate oxide layer padding sidewalls of said trenched gate.

7. The power semiconductor power device of claim 1 wherein:

said implanting-ion block having a width less than a lateral diffusion length of body dopant ions implanted into said body region.

8. The power semiconductor power device of claim 1 further comprising:

an insulation protective layer disposed on top of said semiconductor power device having a plurality of contact openings opened therethrough and extending to said body region and said semiconductor power device further including a source/body ohmic contact dopant region disposed beneath each of said contact openings for enhancing ohmic contact to said body/source region.

9. The power semiconductor power device of claim 1 wherein:

said mesa area having a controlled width and said body region having a predefined depth and dopant concentration for generating a peak electrical field near said inverted V pinnacle point for inducing a breakdown near a bottom of said body region at a distance away from said trenched gate.

10. The power semiconductor power device of claim 1 wherein:

said semiconductor power device further comprising a metal oxide semiconductor field effect transistor (MOSFET) device.

11. The power semiconductor power device of claim 1 wherein:

said semiconductor power device further comprising a N-channel metal oxide semiconductor field effect transistor (MOSFET) device.

12. The power semiconductor power device of claim 1 wherein:

said semiconductor power device further comprising a P-channel metal oxide semiconductor field effect transistor (MOSFET) device.

13. The power semiconductor power device of claim 1 further comprising:

a termination area wherein said implanting-ion block having a greater width than said implanting-ion block on said mesa area for separating said body regions and forming floating body regions in said termination area to form at least a guard ring in a trenched gate surrounded by said floating body region in said termination area.