Content-addressable memory having phase change material devices

Content-addressable memory (CAM) cells comprised of phase change material devices (PCMDs), including PCMD-based binary CAM cells (PCMD-based BCAM cells), PCMD-based ternary CAM cells (PCMD-based TCAM cells), and PCMD-based universal CAM cells (PCMD-based UCAM cells). The PCMDs of the various PCMD-based CAM cells are configured and programmed in a manner that allows a logic "0" or a logic "1" to be stored by the CAM cell. The logic value stored by a given PCMD-based CAM cell depends on the program states of the PCMDs. A program state of a PCMD is determined by whether the phase change material of the PCMD has been allowed to solidify to a crystalline, low-resistance state during a programming operation, or whether the phase change material of the PCMD is forced to solidify to an amorphous, high-resistance state during the programming operation.