Growth on Porous Si Substrates

Initially, a carbonization step, carried out at atmospheric pressure, was used to convert Si into SiC by introducing the C3H8 precursor (100 seem, 3 % C3H8 in H2) during the temperature ramp up to the growth temperature, during which the C atoms attach to the Si dangling bonds of 

One minute after the growth temperature had been reached, the pressure was reduced to 150 Torr and silane introduced into the gas stream. The propane flow was simultaneously reduced to achieve a Si/C ratio of 0.31. Growth took place from this point until the desired run time was reached. This process will be called the cold wall growth process schedule from this point on. 

However, no other dramatic improvement in film quality was observed indicating that these initial experiments require further refinement. 

The high temperature required for the hetero-epitaxial growth of 3C-SiC, is close to the Si melting temperature of 1410 °C, which most likely alters the porous Si substrate structure during growth. Therefore, further analysis of the porous substrates was performed to determine whether the pores could be stabilized before attempting hetero-epitaxial growth. 

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