The latter structure is composed of polycrystalline graphite in fact . a large amount of sic > 2 single crystals with the size of lonm appears in the film when the time of the post - heating is increased to five hours 当退火时间延长到5个小时，薄膜的结晶度和600退火一个小时的薄膜相类似，不过，薄膜中大量存在的是10nm左右的sio2晶粒。
