US 11,929,411 B2
Recessed access devices and methods of forming a recessed access devices
Sau Ha Cheung, Boise, ID (US); Soichi Sugiura, Bristow, VA (US); Jaydip Guha, Boise, ID (US); Anthony Kanago, Boise, ID (US); and Richard Beeler, Boise, ID (US)
Assigned to Micron Technology, Inc., Boise, ID (US)
Filed by Micron Technology, Inc., Boise, ID (US)
Filed on Aug. 25, 2021, as Appl. No. 17/411,643.
Prior Publication US 2023/0063549 A1, Mar. 2, 2023
Int. Cl. H01L 29/423 (2006.01); H01L 29/40 (2006.01); H01L 29/51 (2006.01); H10B 12/00 (2023.01)
CPC H01L 29/4236 (2013.01) [H01L 29/401 (2013.01); H01L 29/42368 (2013.01); H01L 29/512 (2013.01); H10B 12/053 (2023.02); H10B 12/34 (2023.02)] 14 Claims
OG exemplary drawing
 
5. A recessed access device comprising:
a conductive gate in a trench in semiconductor material;
a gate insulator extending along sidewalls and around a bottom of the conductive gate between the conductive gate and the semiconductor material;
a pair of source/drain regions in upper portions of the semiconductor material on opposing lateral sides of the trench;
a channel region in the semiconductor material below the pair of source/drain regions extending along sidewalls and around a bottom of the trench;
the gate insulator comprising a low-k material and a high-k material, the low-k material being characterized by its dielectric constant k being no greater than 4.0, the high-k material being characterized by its dielectric constant k being greater than 4.0, the low-k material extending completely along all of the sidewalls of and directly under the bottom of the conductive gate, the high-k material being laterally-inward of the low-k material and at least one of (a) and (b), where:
(a): extending less-than-completely along all of the sidewalls of the conductive gate; and
(b): not being directly under the bottom of the conductive gate;
comprising the (a); and
comprising the (a) and the (b).