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我们研究了采用电子回旋共振等离子体增强金属有机化学气相沉积 (ECR PEMOCVE)技术在GaAs( 0 0 1 )衬底上外延生长立方GaN的过程中衬底氮化条件对外延膜生长的影响。发现氮化时在氮等离子体中加入氢等离子体对于立方GaN薄膜生长具有显著影响。和氮化过程中不加入氢等离子体相比 ,氮化过程中加入氢等离子体生长出的外延膜其X射线衍射 (XRD)半高宽 (FWHM)可以最高降低 4 0 %以上。原子力显微镜 (AFM)观察表明 :在N2 H2 混合等离子中氮化过的衬底上外延的缓冲层表面变得更为平滑 ,晶粒也变得粗大。最后 ,我们提出了一个化学模型对上述结果进行了分析和解释。
We investigated the effect of substrate nitridation conditions on epitaxial film growth by electron cyclotron resonance plasma enhanced metal-organic chemical vapor deposition (ECR PEMOCVE) technology in the epitaxial growth of cubic GaN on GaAs (0 0 1) substrates. It was found that the addition of hydrogen plasma to nitrogen plasma during nitridation has a significant effect on the growth of cubic GaN films. The epitaxial film grown by hydrogen plasma during the nitriding process can have a maximum FWHM reduction of 40% or more compared with the case where no hydrogen plasma is added during the nitriding process. Atomic force microscopy (AFM) observations indicate that the surface of the buffer layer epitaxial on the nitrided substrate in the N2 H2 mixed plasma becomes smoother and the grains coarse. Finally, we propose a chemical model to analyze and explain the above results.