Semiconductor device with bulb-type recessed channel and method for fabricating the same

• US 8,288,819 B2
• Filed: 11/23/2010
• Issued: 10/16/2012
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Original Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Inventors: Jang, Se Aug, Hong, Kwon, Cho, Heung Jae, Kim, Yong Soo, Yang, Hong Seon, Pyi, Seung Ho, Lim, Kwan Yong, Sung, Min Gyu, Lee, Seung Ryong, Kim, Tae Yoon
• Primary Examiner(s): SANDVIK, BENJAMIN P
• Application Number:
  US12/953,255
• Publication Number:
  US 20110068380A1
• Time in Patent Office: 693 Days
• Field of Search: None
• US Class Current: 257/330
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/66553 using inside spacers, permanent or not
• CPC Class Codes: H01L 29/66621 using etching to form a recess at the gate location etching of semiconductor bodies H01L21/302
• CPC Class Codes: H10B 12/053 the transistor being at least partially in a trench in the substrate vertical transistor in combination with a capacitor formed in a substrate trench H10B12/0383

Abstract

A method for fabricating a semiconductor device includes providing a substrate having a bulb-type recessed region, forming a gate insulating layer over the bulb-type recessed region and the substrate, and forming a gate conductive layer over the gate insulating layer. The gate conductive layer fills the bulb-type recessed region. The gate conductive layer includes two or more conductive layers and a discontinuous interface between the conductive layers.

Claims

1. A semiconductor device comprising:

a substrate;

a bulb-type recessed region formed in the substrate;

a gate insulating layer formed over the bulb-type recessed region and the substrate;

a vacancy-removed first gate conductive layer formed over the gate insulating layer, wherein vacancies melted in equilibrium inside the vacancy-removed first gate conductive layer are diffused out by a thermal treatment;

a second gate conductive layer formed over the vacancy-removed first gate conductive layer to fill in the bulb-type recessed region, and

a discontinuous interface between the vacancy-removed first gate conductive layer and the second gate conductive layer.

2. The semiconductor device of claim 1, wherein a first thickness of the vacancy-removed first gate conductive layer is smaller than half of a width of an opening of the bulb-type recessed region.

3. The semiconductor device of claim 1, wherein the vacancy-removed first gate conductive layer and the second gate conductive layer comprise a silicon layer.

4. The semiconductor device of claim 3, wherein the silicon layer is doped with impurities.

5. The semiconductor device of claim 1, wherein the vacancy-removed first gate conductive layer comprises a silicon layer on which the thermal treatment is performed.