公开(公告)号：US09666680B1

公开(公告)日：2017-05-30

申请号：US14944224

申请日：2015-11-18

Applicant: UNITED MICROELECTRONICS CORP.

Inventor： Yuan-Hsiang Chang ,  Shen-De Wang ,  Chih-Chien Chang ,  Jianjun Yang ,  Aaron Chen

IPC: H01L29/788 ,  H01L29/423 ,  H01L29/66 ,  H01L21/28 ,  H01L21/265 ,  H01L21/321 ,  H01L21/223 ,  H01L21/285 ,  H01L21/3213 ,  H01L21/311 ,  H01L29/51 ,  H01L27/11521

CPC classification number: H01L29/42328 ,  H01L21/26586 ,  H01L21/28273 ,  H01L21/28562 ,  H01L21/31111 ,  H01L21/321 ,  H01L21/32133 ,  H01L27/11521 ,  H01L28/00 ,  H01L29/42324 ,  H01L29/513 ,  H01L29/518 ,  H01L29/66825 ,  H01L29/788

Abstract: A flash cell includes a gate and an erase gate. The gate is disposed on a substrate, wherein the gate includes a control gate on the substrate and a floating gate having a tip between the substrate and the control gate. The erase gate is disposed beside the gate, wherein the tip points toward the erase gate. The present invention also provides a flash cell forming process including the following steps. A gate is formed on a substrate, wherein the gate includes a floating gate on the substrate. An implantation process is performed on a side part of the floating gate, thereby forming a first doped region in the side part. At least a part of the first doped region is oxidized, thereby forming a floating gate having a tip.