The invention provides a phase change memory and a method for forming the phase change memory. The phase change memory includes a storage region and a peripheral circuit region. The peripheral circuit region has a peripheral substrate, peripheral shallow trench isolation (STI) units in the peripheral substrate, and MOS transistors on the peripheral substrate and between the peripheral STI units. The storage region has a storage substrate, an N-type ion buried layer on the storage substrate, vertical LEDs on the on the N-type ion buried layer, storage shallow trench isolation (STI) units between the vertical LEDs, and phase change layers on the vertical LEDs and between the storage STI units. The storage STI units have thickness equal to thickness of the vertical LEDs. Each vertical LED comprises an N-type conductive region on the N-type ion buried layer, and a P-type conductive region on the N-type conductive region. The P-type conductive region contains SiGe. The peripheral STI units have thickness equal to thickness of the storage STI units. A top of P-type conductive region is flush with a top of the peripheral substrate. The P-type conductive region containing SiGe reduces drain current through the vertical LED and raises current efficiency of the vertical LED. The peripheral circuit region can work normally without adverse influence on performance of the phase change memory.