To gain the microscopic understanding on the contact deformation and phase transformation of semiconductor silicon devices, and find out the cause of adhesion. In the use of Morse and Tersoff mixed potential function based on molecular dynamics method, the contact characteristics and the cause of cohesion of mono-crystalline silicon during loading or unloading were analyzed, and the contact deformation and phase transformation of silicon devices were described by the shear strain and coordination number respectively. It was noted that the strain degree decreased gradually from inside to outside in the close contact area between the silicon substrate and the probe during loading, and the strain degree increased gradually from outside to inside during unloading. Moreover, a bridge was formed on contact edge sides during unloading, which indicated that there was a strong adhesion around contact sides and it served as the main cause for inducing some silicon-based atoms to adhere to the probe surface. In addition, the underlying reason of the produced occlusion adhesion could attribute to the destruction of the bond energy of the phase transformation of silicon atoms when the silicon substrate was loaded. At the same time, some of the strain energy accumulated during the loading was released during unloading, so that the close contact area between the silicon substrate and the probe partially destroyed the adhesion of atoms to the peripheral contour of the probe, resulting in obvious adhesion. Furthermore, the silicon-based phase transformation during loading and unloading was mainly Bct5-Si, and the contact deformation with adhesive effect and phase transformation in mono-crystalline silicon got affected as temperature increased. In other words, the higher temperature was, the more random rough ripples would appear on the silicon surface, and the enhanced effect of the adhesion was more likely to be affected by the temperature during unloading, which was the fundamental cause that led to the failure of semiconductor micro/nano devices. The dynamic contact deformation and phase transformation for semiconductor silicon devices are significantly dependent on temperature, and the softening deformation caused by the increase of temperature is the main reason for enhanced adhesion. This research gains a deeper understanding on the contact behavior and the cause of adhesion of semiconductor devices under high temperature and heavy load conditions.