HIGH TEMPERATURE FURNACE FOR LIQUID PHASE EPITAXY OF SILICON CARBIDE IN MICROGRAVITY

摘要

The high temperature furnace for Liquid Phase Epitaxy (LPE) was developed by Swedish Space Corporation. It was developed for a Silicon Carbide liquid phase epitaxy microgravity experiment performed by Linkoping University, Sweden. The LPE is capable of processing materials up to l900 deg. C in ultra clean atmosphere or vacuum in accordance with requirements for semiconductor crystal growth. The LPE has the capability to heat and cool the samples rapidly due to a high power input and a cooling gas system, this makes it possible to utilise it for short duration microgravity flights. The samples can be processed in isothermal conditions or with a temperature gradient up to 5"C/mm. The two resistive heaters are controlled individually which makes it possible for the user to pre-program an optional temperature profile for the experiment. The LPE was launched on the European microgravity rocket MASER 7 at Esrange in May l996. For the first time under microgravity conditions four SiC samples were processed successfully. SiC has in comparison with Si superior properties regarding power electronics[l]. However, the quality of the material needs to be improved considerably before commercial production. Growth from a solution may give rise to an impurity microsegregation and growth instabilities due to the gravitation-induced convection, presumably resulting in an alteration of the point defect assembly. Growth under micro- gravity is thus a key for a better understanding of the growth process and defect formation. The ma- terial grown in microgravity is improved compared with on-grou