Analysis Of The Thermal Effect In The Interaction Of The Laser With Semiconductor Material

The thermal effect of the interaction of the laser with semiconductor material is one of the most important physics phenomena when the laser irradiates semiconductor surface. The laser-induced heating lead to the temperature raise of semiconductor surface and the heat diffusion, heat expansion and the change with thermal stress, and may be likely to cause the ablation of the semiconductor material. If the laser's power enough, some parts of the semiconductor material on the surface may be melt or evaporate. It possibility lead to the semiconductor material change or lose the original function. Thus we can take the advantage of the laser to drill the holes, cut, and ablate the semiconductor material and so on. Therefore, the studies of the thermal effect during the interaction of the laser with semiconductor and the calculation of the temperature field not only on the surface but also inside the targets form are the basis of the technologies such as the laser processing and the technology of laser heat treatment. For some typical problems on laser heating, the thermal models have been built and the approximate analytical expression have been obtained according to some certain assumptions and the boundary conditions. But the analytical expressions are only applicable when the simpler situations and the results obtained are also approximate. The numerical analysis is more flexible and is able to deal with the more complicate problems. As long as the physical models describing the process of the ablation are reasonable, we can get the appropriate results. In this paper, the research of the temperature raise in the semiconductor material irradiated by the long pulses laser and ultrashort pulses laser are separately performed. The main results can be summarized as follows:1. Based on the thermal conduction equation, the temperature raising distribution of several typical detector irradiated by long laser pulse are both numerically calculated using a 1-D model of heat conduction and by means of the implicit schemes different expression. The relation of the temperature raise with the laser power density,the pulse duration and thickness of semiconductor material are discussed.2. To describe ultrashort laser ablation on the surface of semiconductor material, numerical simulation of the double-temperature equation (DFE) by finite-difference method (FDM). The temperature field of ultrashort pulse laser ablation on semiconductor is given, and the laser damage threshold is calculated, It shows that metal and semiconductor have the same time of the couple with carrier and lattice. Furthermore, the different pulse duration and the different laser power density affect the temperature of the surface of semiconductor, it shows that laser pulse power density is the main factor affecting temperature of carrier.3. Based on double-temperature equation and carrier transport dynamic model, the carrier transport dynamic model and double-temperature equation are performed by finite-difference method (FDM). The temperature, the density field of carrier and lattice are shown, the relations of photoconductive (PC) detector temperature rising with the laser power density and the pulse duration time are performed.