© 2017 IEEE. In this paper, phase-change materials and memory devices for internet of everything (IoT) application will be discussed. For better reliability and retention, doping N into GeTe with a fast operation speed was investigated with the aim of reducing the volume change upon crystallization. For high-density, the multilevel storage was investigated using SbTeN-based devices and several resistance levels with good stability were demonstrated, which resulted mainly from the gradual enlargement of crystalline region between electrodes by Joule heating. For low power consumption, phase-change memory (PCM) incorporated with nanostructures was investigated and was proved to be very energy-efficient.