Invention Grant
US08797800B1 Select gate materials having different work functions in non-volatile memory
有权
选择在非易失性存储器中具有不同功能的栅极材料
- Patent Title: Select gate materials having different work functions in non-volatile memory
- Patent Title (中): 选择在非易失性存储器中具有不同功能的栅极材料
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Application No.: US14279411Application Date: 2014-05-16
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Publication No.: US08797800B1Publication Date: 2014-08-05
- Inventor: Yingda Dong , Masaaki Higashitani
- Applicant: SanDisk Technologies Inc.
- Applicant Address: US TX Plano
- Assignee: SanDisk Technologies Inc.
- Current Assignee: SanDisk Technologies Inc.
- Current Assignee Address: US TX Plano
- Agency: Vierra Magen Marcus LLP
- Main IPC: G11C16/04
- IPC: G11C16/04 ; H01L27/115

Abstract:
In a 3D stacked non-volatile memory device, multiple smaller drain-end selected gate (SGD) transistors replace one larger SGD transistor. The SGD transistors have different work functions in their control gates so that, during a programming operation, a discontinuous channel potential is created in an inhibited NAND string. The SGD transistor closest to the bit line has a higher work function so that the channel potential under it is lower, and the next SGD transistor has a lower work function so that the channel potential under it is higher. The different work functions can be provided by using different control gate materials for the SGD transistors. One option uses p+ polysilicon and n+ polysilicon to provide higher and lower work functions, respectively. Metal or metal silicide can also be used. A single SGD transistor with different control gate materials could also be used.
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