Theoretical Investigation of the thermodynamic stability and Density of States in α-(Co, Cu)Sn3

With the development of electronic packaging, the performance of microchip is crucial for the reliability of solder joints. The α-CoSn
₃
with some performance have been studied by researchers continuously. However, there is a little study on doping α-(Co, Cu)Sn
₃
that Cu is regard as a common element of electronic packaging. In this paper, different concentrations of Cu (0~9.375 at.%) were used to replace the Co atoms in α-CoSn
₃
intermetallic(IMC). The thermodynamic stability and electronic structure of α-(Co, Cu)Sn
₃
were calculated by the first-principles. The results show that the formation enthalpy and cohesive energy of α-(Co
_1-x
, Cu
_x
)Sn
₃
(x=0~0.375) are negative values, means the α-(Co, Cu)Sn
₃
configurations can be formed and exist stably. With the increasing of Cu atoms, the formation enthalpy and cohesive energy increased, the formation of α-(Co, Cu)Sn
₃
became difficult and unstable configurations. By analyzing the density of states(DOS) , the increasing of Cu atoms make the main peak deviate from Fermi level gradually and form two main peaks under Fermi level. Besides, the increase of Cu concentrations decreases NEF, indicating the bonding is weakened.