access icon free Finite element electro-thermal modelling of nanocrystalline phase change elements using mesh-based crystallinity approach

Phase change memory cells composed of nanocrystalline Ge2Sb2Te5 with a heater diameter of 10 nm and Ge2Sb2Te5 thickness of 100 nm are studied by using two-dimensional finite element simulations with COMSOL Multiphysics. The nanocrystalline Ge2Sb2Te5 is emulated by using a mesh-based model incorporating crystalline grains of random size and location embedded in the amorphous media. The material parameters are modelled with temperature dependency from 300 to 1000 K, including electrical resistivity, thermal conductivity, electric field breakdown and Seebeck coefficient. This model is shown to capture the cycle-to-cycle and device-to-device variability in phase change memory cells.

Inspec keywords: Seebeck effect; phase change memories; germanium compounds; chalcogenide glasses; phase change materials; antimony compounds; nanostructured materials; electric breakdown; electrical resistivity; thermal conductivity; mesh generation

Other keywords: phase change memory cells; electrical resistivity; two-dimensional finite element simulations; nanocrystalline phase change elements; Ge2Sb2Te5; cycle-to-cycle variability; size 100 nm; Seebeck coefficient; amorphous media; crystalline grains; electric field breakdown; material parameters; device-to-device variability; random size; COMSOL multiphysics; temperature 300 K to 1000 K; mesh-based crystallinity approach; finite element electrothermal modelling; size 10 nm; thermal conductivity

Subjects: Finite element analysis; Electrical conductivity of amorphous and glassy semiconductors; Thermoelectric effects (semiconductors/insulators); Glasses (engineering materials science); Amorphous and glassy semiconductors; Memory circuits; Nonelectronic thermal conduction and heat-pulse propagation in nonmetallic solids

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through the phases