US 9,812,558 B2
Three-dimensional transistor and methods of manufacturing thereof
Jhih-Yang Yan, Taipei (TW); Samuel C. Pan, Hsinchu (TW); Chee Wee Liu, Hsinchu (TW); Hung-Yu Yeh, Taichung (TW); and Da-Zhi Zhang, New Taipei (TW)
Assigned to National Taiwan University, Taipei (TW); and Taiwan Semiconductor Manufacturing Company, Ltd., Hsin-Chu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW); and National Taiwan University, Taipei (TW)
Filed on Mar. 22, 2017, as Appl. No. 15/466,656.
Application 15/466,656 is a division of application No. 14/732,224, filed on Jun. 5, 2015, granted, now 9,627,411.
Prior Publication US 2017/0194464 A1, Jul. 6, 2017
Int. Cl. H01L 21/00 (2006.01); H01L 29/66 (2006.01); H01L 27/12 (2006.01); H01L 21/8234 (2006.01); H01L 21/84 (2006.01); H01L 27/088 (2006.01); H01L 29/08 (2006.01); H01L 21/306 (2006.01); H01L 21/265 (2006.01)
CPC H01L 29/66795 (2013.01) [H01L 21/26513 (2013.01); H01L 21/30604 (2013.01); H01L 21/823412 (2013.01); H01L 21/823418 (2013.01); H01L 21/823431 (2013.01); H01L 21/845 (2013.01); H01L 27/0886 (2013.01); H01L 27/1211 (2013.01); H01L 29/0847 (2013.01); H01L 29/66545 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of forming a device, the method comprising:
forming a mesa over a substrate;
forming a mask layer over a top surface and sidewalls of the mesa, the mask layer exposing a middle portion of a sidewall of the mesa; and
etching to form a vertical recess extending from the exposed middle portion of the sidewall into the mesa, wherein the vertical recess is substantially trapezoidal, V-shaped or U-shaped in a top view, wherein the vertical recess defines a vertically recessed channel region at a narrow end of the vertical recess;
forming a gate stack over the vertically recessed channel region; and
forming a source region and a drain region at a first end and a second end of the vertically recessed channel region, respectively, wherein a length of the gate stack measured along a first direction from the source region to the drain region is equal to or larger than a length of the narrow end of the vertical recess measured along the first direction.