藉由不同週期性藍寶石基板成長氮化鋁並探討其成長機制和材料特性

Abstract

在氮化鋁薄膜磊晶中使用圖案化藍寶石基板(Patterned Sapphire Substrates, PSSs)可以減少穿隧差排密度(Threading Dislocation Density)以增加磊晶品質，以及降低缺陷密度(defect density)。由於業界量產微米尺寸圖案化藍寶石基板，使氮化鋁於成長時所需聚合的厚度較高(8~12um)。我們利用電子束微影技術與濕蝕刻技術，製作出奈米尺寸圖案化藍寶石基板，並成功用3um的厚度達到聚合，並使缺陷密度從 3.25x10^9 cm^(-2) 下降到 4.8x10^8 cm^(-2)。 在最後的階段，我們透過拉曼量測成長於不同週期和頂部c-plane大小的圖案化藍寶石基板的氮化鋁，並以半高寬和所受之殘餘應力為主體提出氮化鋁磊晶機制模型，透過表面與側面SEM，AFM，TEM，晶粒大小，與文獻參考加以驗證，提升可信度。

Using a patterned sapphire substrate(PSSs) in the Aluminum nitride thin film can reduce the threading dislocation density and increase the crystal quality, and reduce the defect density. Due to the size of commercial patterned sapphire substrate is micronmeter, the coalescence thickness will be higher approximately 8 to 12 micronmeter. We used ebeam lithgrophy and wet-etching technology to fabricate nano-PSS and successfully growth the 3um AlN thin film which already coalescence and reduce defect density from 3.25x〖10〗^9 〖cm〗^(-2) to 4.8x〖10〗^8 〖cm〗^(-2). At the final stage, we used raman system to analyze AlN which growth on patterned sapphire with the change between top c-plane size and period.Accroding the result of FWHM and residual stress, we establish the growth mechanism model of AlN.Finally we prove it with SEM,AFM,TEM.