Si3N4/Si表面Si生长过程的扫描隧道显微镜研究

利用原位掃描隧道顯微鏡和低能電子衍射分析了Si的納米顆粒在Si3N4 /Si(111)和Si3N4 /Si(10 0 )表面生長過程的結構演變 .在生長早期T為 35 0— 10 75K范圍內 ,Si在兩種襯底表面上都形成高密度的三維納米團簇 ,這些團簇的大小均在幾個納米范圍內 ,并且在高溫退火時保持相當穩定的形狀而不相互融合 .當生長繼續時 ,Si的晶體小面開始顯現 .在晶態的Si3N4 (0 0 0 1) /Si(111)表面 ,Si的 (111)小面生長比其他方向優先 ,生長方向與襯底Si(111)方向一致 .最后在大范圍內形成以 (111)為主的晶面 .相反 ,在非晶的Si3N4 表面 ,即Si3N4 /Si(10 0 ) ,Si晶體的生長呈現完全隨機的方向性 ,低指數面如 (111)和 (10 0 )面共存 ,但它們并不占據主導地位 ,大部分暴露的小面是高指數面如 (113)面 .對表面生長過程進行了探討并給出了合理的物理解釋. The growth of Si on silicon nitride surfaces has been studied using in situ STM, low energy electron diffraction and Auger electron spectroscopy.In the early stage( T =350 —1075 K) , Si nano-clusters can appear on different substrates. These clusters are round with sizes in the range of several nanometers.T hey are also rather stable when the substrate temperature changes ( or annealing) .As these clusters grow continually, crystalline facets start to form .On the crystalline Si3N4 ( 0001) / Si(111) , Si islands with ( 111)-oriented top facets grow faster than others, and they are aligned with the original Si(111) substrate.Finally, Si( 111) became the dominant feature on the whole surface.In contrast, on the amorphous Si3N4 surface, Si islands grow in random orientation .Low-index facets, such as ( 111) and ( 100) , and high-index facets, such as ( 113) , coexist .Some discussions are given to explain the above grow th procedures .