US Patent 8966330 Bad block reconfiguration in nonvolatile memory

When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.