Study On Heat Conduction Mechanism Of Sb₂Te₃,Sb₂Te And N-doped GST Thin Film Phase Change Storage Films

As an important phase change material,Sb2Te3 and Sb2 Te are widely used because of their important practical value and potential application prospects.For example,multimedia data CD(DVD)and CVD.By studying them heat conduction and analysis of them mechanism can not only extend the application field of phase-change materials.It also provides a theoretical basis for understanding the nature of the phase change material themself.Ge2Sb2Te5(GST)has the advantages of fast crystallization speed,optical properties of amorphous and crystalline state,and great difference in electrical properties.It is the most studied and widely used phase change storage material.However,as the size of memory equipment is decreasing,some performance deficiencies gradually limit the application of GST,such as crystal resistivity,low crystallization temperature and poor thermal stability,etc.The study found that doping can improve the performance of the phase change material itself,such as thermal performance and electrical properties,so the doping of phase change materials can improve the performance of the phase change material itself.In this paper,the thermal conductivity measurement and mechanism of Sb2Te3,Sb2 Te and N doped GST films were studied..Through constructing 3? device and the preparation of 3? samples,establish 3? method to measure thin film heat transfer system.Create 3?device when choosing the appropriate hardware materials,such as prober,phase-locked amplifier and temperature control devices,etc.And write the program in Mat Lab.Design of electrode materials between the dielectric layer and transition layer and template to design and manufacture of mask.3? sample preparation,preparation thin film by magnetron sputtering and lithography on the electrode.3? heat conduction measurement system was used to measure Sb2Te3 and Sb2 Te film of heat conduction and to analyze its mechanism.The results showed that the thermal conduction of Sb2Te3 was larger than that of Sb2 Te,because the deposition state of Sb2Te3 was partially crystallized and Sb2 Te was amorphous.After the annealing treatment of473 K,the thermal conductivity of Sb2 Te is much larger than that of Sb2Te3,and the results show that the thermal conductivity of the annealed Sb2 Te has a greater dependence on temperature.The thermal conduction mechanism of each film was analyzed by WF law and debye model.Found Sb2Te3 phonon heat conduction dominated in low temperature,film deposition state of conductivity is low,the contribution of free electrons sample for deposition state heat conduction basic can be ignored,room temperature more thanelectronic heat transfer enhanced gradually.The phonon heat conduction of Sb2 Te increases with temperature at low temperature,and decreases near 310 K,because the decrease of phonon contribution determines that the whole thermal conduction of Sb2 Te decreases with the increase of temperature.Preparation thin film by magnetron sputtering,determined by AFM surface roughness measuring film deposition and 60 w power of 20 W,when deposition power of 20 W,different N doping GST membrane nitrogen argon flow rate ratio ",respectively,1:15,1:20,25 and1:30 through XPS results show that the doped N and GST in Ge atoms,generated the Ge-N key.When the power is 60 W,the flow ratio is 1:15,2:20,3:21 and 4:20,and the N content of the four groups is made of the film,and the measured N content is 5.37 atom%,5.57 atom%,7.8atom%,7.76 atom%.The resistivity and selebek coefficient of n-gst films with a ratio of N-GST and power of 60 W were measured by the ratio of N-GST films with different N-GST and power of 20 W.It is found that the resistivity decreases with the increase of temperature,and the seebeck coefficient increases first and then decreases.Mainly because as the temperature increases,the film gradually crystallizes.Has no mutation and resistivity measurements,prove the film crystallization is a gradual process,and the addition of nitrogen,formed more defects and distortion,is likely to hamper the film crystallization speed.The heat conduction of N doped GST films with sedimentary and annealing states was measured when the deposition power was 60 W.Found sedimentary state when the thermal conductivity increases with the increase of nitrogen content,This is because the n-gst films are amorphous in the depositional state,and the free carriers are very few in the film,and the heat conduction basically depends on the phonon conduction.With N atoms doping,the number of free carrier in film,electronic heat conduction part increases gradually,thus led to the overall thermal conductivity increased with the increase of doping concentration increased.The annealing thermal conductivity decreases with the increase of N content.It is because the lattice heat conduction of GST film increases greatly in the crystalline state,and the free electron(hole)in the film increases,and the electron heat conduction also increases.N elements join increases the concentration of defects,which leads to the scattering of the carrier,the defect concentration,the greater the phonon and the greater the scattering of free electrons,therefore,with the increase of N content,thermal conductivity decreases.