| 2. | The quality of buffer layer and thin films was analyzed by afm , xrd , rheed and xps respectively . the effect of the experimental parameters such as carbonization time , working pressure , c source gas flow rate , carbonization temperature , different carbonization gas and substrate on the carbonization process was studied firstly . it was observed that the size of particles was increased with the increase of carbonization time and the rms was opposite , but the trend was reduced while the carbonization time was long enough ; the size of particles was increased with the increase of working pressure too , and choosing a proper working pressure could get a smooth surface ; the size of particles was unobviously changed while the gas flow rate was low , but it was notability increased with the increase of gas flow rate while the gas flow rate was high enough , and a smooth surface could be also obtained by choosing a proper gas flow rate ; with the increase of carbonization temperature , the size of particles was increased , the rms is decreased and a good single - crystalline carbonization layer could be obtained , but a rough surface was formed at a excessive high temperature ; the rms of
对于碳化工艺,侧重研究了碳化时间、反应室气压、 c源气体的流量、碳化温度以及不同种类的c源气体、基片取向等因素对碳化层质量的影响,研究结果表明:随着碳化时间的增长,碳化层的晶粒尺寸随之变大,表面粗糙度随之降低,但当碳化到一定时间之后,碳化反应减缓,碳化层的晶粒尺寸以及表面粗糙度的变化幅度变小;碳化层的晶粒尺寸随反应室气压的升高而变大,适中的反应室气压可得到表面比较平整的碳化层;在c源气体的流量相对较小时,碳化层的晶粒尺寸随气体流量的变化不明显,但当气体流量增大到一定程度时,碳化层的晶粒尺寸随气体流量的增大而明显变大,同时,适中的气体流量得到的碳化层表面粗糙度较低;碳化温度较低时,碳化层的晶粒取向不明显,随着碳化温度的升高,碳化层的晶粒尺寸明显变大,且有微弱的单晶取向出现,但取向较差,同时,适中的碳化温度可得到表面平整的碳化层;相比于c _ 2h _ 2 ,以ch _ 4作为c源气体时得到的碳化层表面平整得多;比起si ( 100 ) ,选用si ( 111 )作为基片生长的碳化层的晶粒取向一致性明显更好。 |
