I asked Perplexity.ai to list all of the DRAM manufacturing companies that it could. What follows is that list:

Samsung Electronics – https://www.samsung.com

SK hynix – https://www.skhynix.com

Micron Technology – https://www.micron.com

ChangXin Memory Technologies (CXMT) – https://www.cxmt.com

Nanya Technology – https://www.nanya.com

Winbond Electronics – https://www.winbond.com

Powerchip Semiconductor Manufacturing Corp. (PSMC) – https://www.psmc.com.tw

Fujian Jinhua Integrated Circuit (JHICC) – http://www.jhicc.com

GigaDevice – https://www.gigadevice.com

Etron Technology – https://www.etron.com

Integrated Silicon Solution Inc. (ISSI) – https://www.issi.com

Elite Semiconductor Memory Technology (ESMT) – https://www.esmt.com.tw

Zentel Electronics – https://www.zentel.com.tw

Alliance Memory – https://www.alliancememory.com

AP Memory Technology – https://www.apmemory.com

AMIC Technology – https://www.amictechnology.com

Hua Hong Semiconductor – https://www.huahong.com

(Note that I have not researched each of these companies individually... There may be errors in the above list (some may be DRAM resellers, some may be defunct, etc., etc.))