High speed serial access semiconductor memory with fault tolerant feature

摘要

A semiconductor memory device of the single-chip MOS/LSI one-transistor dynamic RAM cell array type stores both data and address in rows of the array and uses a high speed serial access shift register as its data input/output system. The serial shift register has a number of stages equal to the number of columns in the memory cell array, and data in the shift register is transferred into or out of the columns of the array when a comparator indicates that an address input matches the stored row address. The rows are sequentially activated by a commutator, so no row or column decoders are needed. The device may be made fault tolerant by use of an electrically programmable floating gate transistor connected to each row, and programming this transistor to blank input or output if the row includes bad cells. The fault tolerant feature is transparent to the computer system using the memory.