Suzuki Mineharu, Urushihara Nobuaki, Sanada Noriaki, Paul Dennis F, Bryan Scott, Hammond John S
ULVAC-PHI, Inc., Chigasaki, Kanagawa 253-8522, Japan.
Anal Sci. 2010;26(2):203-8. doi: 10.2116/analsci.26.203.
Cross-sections of GaAs/AlAs thin films prepared by cleavage of MBE-grown superlattices have been analyzed with Auger electron spectroscopy with a spatial resolution of 6 nm. Elemental distributions of Ga, Al, and As were clearly distinguished in line analysis as well as in two dimensional mapping for 50, 20, and 10 nm thin film structures. We have found an oscillation of Al KLL peak position between the two values while the peak positions of Ga LMM and As LMM remain constant. The origin of the Al KLL peak shift is a primary electron beam induced reduction of oxidized Al atoms formed during specimen preparation. The Auger spectra of Al oxide are generated by scattered electrons at regions with small amounts of electron dose, corresponding to AlAs areas further than 10 to 25 nm from the primary beam. The intensity of the Al KLL peaks excited by scattered electrons from the 25 kV primary electron beam is about 10% of the Ga LMM peak intensity originating from the GaAs stripe.
通过劈裂分子束外延（MBE）生长的超晶格制备的GaAs/AlAs薄膜的横截面已采用空间分辨率为6纳米的俄歇电子能谱进行分析。在50纳米、20纳米和10纳米薄膜结构的线分析以及二维映射中，Ga、Al和As的元素分布都能清晰区分。我们发现，Al KLL峰位置在两个值之间振荡，而Ga LMM和As LMM的峰位置保持不变。Al KLL峰位移的起源是在样品制备过程中形成的氧化Al原子被一次电子束诱导还原。Al氧化物的俄歇谱是由少量电子剂量区域的散射电子产生的，对应于距离一次束10至25纳米以外的AlAs区域。由25 kV一次电子束的散射电子激发的Al KLL峰强度约为源自GaAs条纹的Ga LMM峰强度的10%。
