Downey S W, Kopf R F, Schubert E F, Kuo J M
Appl Opt. 1990 Nov 20;29(33):4938-42. doi: 10.1364/AO.29.004938.
Resonance ionization mass spectrometry (RIMS) of neutral atoms sputtered from III-V compound semiconductors such as Al(x)Ga(1-x)As provides information that is complementary to secondary ion mass spectrometry with the added advantages of rejecting mass interferences, retaining good sensitivity, and reducing matrix effects. A GaAs sample, delta doped with Be, is used to measure depth resolution and Be secondary ion and atom yield. Because of the coupling of the pulsed RIMS lasers and continuous sputtering beam, duty cycle factors are used to determine the atom yield. A 3-D model of the geometrical overlap of laser and sputtered atoms is developed to ascertain the same utilization efficiency in RIMS. About 30% of the atoms sputtered in 1 micros are calculated to be in the laser beam. The atom yield was found to be near unity. The time-gated RIMS useful yield is ~2%. RIMS is used to minimize matrix effects in a depth profile of a Be-implanted AlAs/A1(0.2)Ga(0.8)As heterostructure and shows that Be diffuses from higher Al-containing layers at concentrations near 10(19) cm(-3). The atomization of As is shown to be affected by the Al content in a GaAs/Al(0.5)Ga(0.5)As structure.
从III-V族化合物半导体（如Al(x)Ga(1-x)As）溅射出来的中性原子的共振电离质谱（RIMS）提供的信息，与二次离子质谱互补，还具有排除质量干扰、保持高灵敏度以及降低基体效应等额外优势。使用一个δ掺杂Be的GaAs样品来测量深度分辨率以及Be二次离子和原子产率。由于脉冲RIMS激光与连续溅射束的耦合，需使用占空比因子来确定原子产率。建立了激光与溅射原子几何重叠的三维模型，以确定RIMS中的相同利用效率。计算得出，在1微秒内溅射的原子中约有30%处于激光束中。发现原子产率接近1。时间选通RIMS的有用产率约为2%。RIMS用于使Be注入的AlAs/A1(0.2)Ga(0.8)As异质结构深度剖析中的基体效应最小化，结果表明Be从Al含量较高、浓度接近10(19) cm(-3)的层中扩散出来。结果表明，在GaAs/Al(0.5)Ga(0.5)As结构中，As的原子化受Al含量的影响。
