NVRAM utilizing high voltage TFT device and method for making the same
    74.
    发明授权
    NVRAM utilizing high voltage TFT device and method for making the same 失效
    采用高压TFT器件的NVRAM及其制造方法

    公开(公告)号:US6022770A

    公开(公告)日:2000-02-08

    申请号:US47155

    申请日:1998-03-24

    CPC分类号: H01L27/105

    摘要: Breakdown and latch-up of field effect transistors integrated with non-volatile semiconductor memory cells requiring voltages higher than logic level voltages for write and erase operations is avoided while limiting process complexity and constraints and increasing potential integration density by using thin film transistors for high voltage switching and isolating the thin film transistors from the substrate by forming the thin film transistors on isolation structures extending between or over elements formed at a surface of a substrate or semiconductor layer. Geometry and doping levels of the thin film transistors is thus made independent of geometry and doping levels of the non-volatile semiconductor memory cells and other field effect transistors operating at lower logic-level voltages. In particular, the thickness of a doped semiconductor layer in which an impurity well may be formed can be determined in a manner to optimize performance of transistors operating at logic level voltages rather than the breakdown voltage which must be withstood by transistors used for controlling write and erase operations of the non-volatile memory cells.

    摘要翻译: 集成在非易失性半导体存储器单元中的场效应晶体管的击穿和闭锁需要高于写入和擦除操作的逻辑电平电压,同时通过使用薄膜晶体管来实现高电压,从而限制工艺复杂性和约束并增加潜在的集成密度 通过在形成在衬底或半导体层的表面上的元件之间或之上延伸的隔离结构上形成薄膜晶体管,从而将薄膜晶体管与衬底隔离开来并隔离。 因此,薄膜晶体管的几何和掺杂水平独立于在较低逻辑电平电压下工作的非易失性半导体存储器单元和其它场效应晶体管的几何形状和掺杂水平。 特别地,其中可以形成杂质阱的掺杂半导体层的厚度可以以优化以逻辑电平电压工作的晶体管的性能而不是由用于控制写入的晶体管所必须承受的击穿电压的方式来确定, 擦除非易失性存储单元的操作。