US 12,484,218 B2
Electrically erasable programmable read only memory cell and forming method thereof
Aaron Chen, Singapore (SG); Chi Ren, Singapore (SG); and Chao-Sheng Hsieh, Singapore (SG)
Assigned to UNITED MICROELECTRONICS CORP., Hsin-Chu (TW)
Filed by UNITED MICROELECTRONICS CORP., Hsin-Chu (TW)
Filed on Apr. 8, 2024, as Appl. No. 18/629,926.
Application 18/629,926 is a division of application No. 17/527,182, filed on Nov. 16, 2021, abandoned.
Claims priority of application No. 202111230640.8 (CN), filed on Oct. 22, 2021.
Prior Publication US 2024/0260263 A1, Aug. 1, 2024
Int. Cl. H10B 41/30 (2023.01); H10B 41/60 (2023.01)
CPC H10B 41/30 (2023.02) [H10B 41/60 (2023.02)] 9 Claims
OG exemplary drawing
 
1. A method of forming an electrically erasable programmable read only memory (EEPROM) cell, comprising:
sequentially forming a floating gate layer and a control gate stacked on a substrate;
forming a first spacer on the floating gate layer and at a first side of the control gate;
removing an exposed top of the floating gate layer to form a pre-floating gate layer, wherein the pre-floating gate layer has a stepped side part;
forming a second spacer on the pre-floating gate layer and on the first side of the control gate; and
removing the exposed part of the pre-floating gate layer, so as to form a floating gate, wherein the floating gate has a two-step side part.