Effects of bottom electrode and environmental insulator on thermal distribution of edge contact-type PRAM cell

Thermal characteristics of edge contact-type phase change random access memory cells have been investigated with different combinations of bottom electrode and insulator such as Ti and SiO2, Ti and AlN, and TiN and AlN. At the same melting temperature on the programmable point of Ge2Sb2Te5, we have determined heat flux for each combination: for the Ti and SiO2, the heat flux is 3.5×105 J/mm2 s, for the Ti and AlN, and the TiN and AlN, they are 1.7×106 and 1.9×104 J/mm2 s, respectively. These simulated results mean that the combination of TiN and AlN is the most effective for the fast response of phase changing from the amorphous to the crystalline and vice versa since the TiN has lower thermal conductivity than the Ti and the AlN has higher thermal conductivity than SiO2.