公开(公告)号：WO1981003393A1

公开(公告)日：1981-11-26

申请号：PCT/US1981000647

申请日：1981-05-14

Applicant: NCR CORP

Inventor： NCR CORP ,  VELTHOVEN A

IPC: G11C13/00

CPC classification number: G11C11/403 ,  G11C14/00 ,  G11C16/0466 ,  H01L27/108

Abstract: The invention is concerned with the problem of reducing the chip area occupied by volatile/nonvolatile dynamic RAM (random access memory) cells. A volatile/non-volatile dynamic RAM cell (30, 80) includes a storage capacitor (32) for volatilely storing binary information during normal RAM operation; an alterable-threshold storage capacitor (33A or 83) for non-volatilely storing the information in non-volatile fashion during poweroff conditions; and an energy barrier (33F or 45) between the two capacitors. Information can be restored to the volatile capacitor either by CCD charge transfer or by charge-pumped operation. The energy barrier facilitates efficient charge pumped restore of information. In one embodiment, the energy barrier is a high concentration substrate surface region (45) having the same conductivity type as the substrate. Alternatively, the alterable-threshold non-volatile capacitor and the energy barrier are provided by a split-gate capacitor (33) which has an alterable threshold non-volatile section (33A) (the non-volatile capacitor) and a non-alterable threshold section (33F) (the energy barrier). The cells may be arranged in an array.

Abstract translation: 本发明涉及减少由易失性/非易失性动态RAM（随机存取存储器）单元占用的芯片面积的问题。 易失性/非易失性动态RAM单元（30,80）包括用于在正常RAM操作期间用于挥发地存储二进制信息的存储电容器（32） 用于在断电条件期间以非易失性方式非易失地存储信息的可变阈值存储电容器（33A或83） 和两个电容器之间的能量势垒（33F或45）。 信息可以通过CCD电荷转移或电荷泵送操作恢复到易失性电容器。 能量屏障有助于有效的电荷泵浦恢复信息。 在一个实施例中，能量势垒是具有与衬底相同的导电类型的高浓度衬底表面区域（45）。 替代地，可变阈值非易失性电容器和能量势垒由具有可变阈值非易失性部分（33A）（非易失性电容器）和不可更改阈值的分离栅极电容器（33）提供， （33F）（能量屏障）。 单元可以排列成阵列。