IBM gets patent for hi-temp PCM (phase-change memory) cell structure

Tom’s Hardware is reporting that IBM recently obtained a patent on specially formulated phase-change memory (PCM) that will operate above 150°C. This is a significant achievement because PCM has a problem with ambient thermal annealing. If the chip temperature goes too high, then the phase-change memory cells will start to self erase as they change from their amorphous state to a crystalline state. This was not a problem for the recently announced LPDDR2 PCM/SDRAM combo device from Micron. (See “3D Thursday: Micron stacks Phase-Change Memory and SDRAM”) I know it’s not a problem for the device’s 0-85°C temperature range because I asked about that problem. Operating at more than 150°C is yet another story entirely.