高阻隔铝塑膜辉光放电发射光谱深度谱测量参数的优化

Optimization of Working Parameters of Glow Discharge Optical Emission Spectrometry of High Barrier Aluminum Plastic Film

脉冲-射频辉光放电发射光谱(GDOES)深度剖析是一种基于辉光放电原理的原子光谱技术,广泛应用于薄膜材料与功能多层膜结构中成分随深度分布的表征。该技术具有真空度要求低,灵敏度高,溅射速率快等优点。同时脉冲-射频电源所采用的瞬间高功率模式可使得氩离子周期性轰击样品表面,避免了由于热量积累所导致的熔融或碳化,因此脉冲-射频辉光放电发射光谱可以用于热敏材料、柔软或脆性等材料的测试,使得GDOES的应用范围由导体扩展至半导体,绝缘体甚至是有机物材料,是深度谱测量的理想选择。铝塑膜作为一种多层复合膜材料是重要的包装材料,具有耐温、耐候性、耐水以及耐酸碱等性能,广泛应用于食品,电子类,国防尖端产品的包装。利用脉冲-射频辉光放电发射光谱深度剖析技术对市场上同一款的高阻隔铝塑膜进行了Pulsed-RF-GDOES深度剖析测量,分析了在不同气压、不同功率、不同气体氛围下,测量深度谱的深度分辨率,溅射速率和信噪比的变化,获得了对铝塑膜进行深度谱测量优化的工作参数。并以相对强度较大的铝信号作为标定,定量计算了测量铝塑膜深度谱的深度分辨率,溅射速率和信噪比。实验结果表明,利用脉冲信号以及氩-氧(4 Vol%)混合气体能有效降低铝塑膜进行深度剖析的热效应,从而扩大参数的调节范围;溅射速率随着功率和工作气压的增加而增加;深度分辨率与功率并非是一个单调函数,存在多个拐点。当溅射功率为40 W时,深度分辨率为最佳;在溅射压强大于950 Pa时,深度分辨率基本不变;信噪比随功率的增加而增加,随气压的增加而减少;使用氩-氧(4 Vol%)混合气体作为溅射气体时,测量信号的分辨率与信噪比均大幅优于纯氩气。实验获得的最佳深度谱测量参数为:氩-氧混合工作气压950 Pa,功率40 W,脉冲频率3000 Hz,占空比为0.1875。

Pulsed-RF-glow discharge optical emission spectroscopy(GDOES)is a kind of atomic spectroscopy technology based on the principle of glow discharge,which is widely used to characterize the depth distribution of components in thin-film materials and functional multilayer structures.This technique has the advantages of low vacuum requirement,high sensitivity,and fast sputtering rate.Meanwhile,the instantaneous high-power mode adopted by the pulsed RF power supply makes the periodical bombardment of the sample surface by argon ions,which avoids the melting or carbonization caused by heat accumulation.Therefore,the pulsed-RF-GDOES can be used to analyse the thermal sensitive materials,soft or brittle materials,etc.,extending the application range of glow discharge emission spectrum from conductive materials to semiconductor and insulator ones.It is an ideal technique for depth profiling of organic films.As a kind of multilayer composite material,aluminum plastic film is an important packaging material with temperature,weather,water,and acid-base resistance.It has been widely used in packaging food,electronics,and national defense cutting-edge products.In this paper,the depth profiles of high barrier aluminum-plastic films are measured using GDOES.The depth resolution,sputtering rate and signal-to-noise ratio of the measured GDOES depth profiles are quantitatively analyzed under different working parameters to obtain the optimized working parameters.The depth resolution,sputtering rate and signal-to-noise ratio of the GDOES depth profile are calculated quantitatively,with the aluminum signal having relatively high intensity as a calibration peak.The experimental results show that the thermal effect could be significantly reduced by applying the pulsed-radio-frequency power and the mixture gas of Ar and O_(2),thus expanding the adjustment range of the working parameters.The sputtering rate increases with increasing the sputtering power and gas pressure,the sputtering rate increases;The relationship between depth resolution and power values is a nonmonotonic function with some inflection points.When the sputtering power is 40 W,the depth resolution is optimized;When the sputtering pressure is higher than 950 Pa,the depth resolution is unchanged;With increasing the sputtering power,signal-to-noise ratio increases;with increasing the gas pressure,signal-to-noise ratio decreases.The depth resolution and signal-to-noise ratio are much better by using the mixture gas of Ar and O_(2)(4 Vol%)than that using the pure Ar gas.The optimized working parameters for the GDOES depth profiling of aluminum plastic film are mixture gas of Ar and O_(2),working pressure of 950 Pa,power of 40 W,pulsed frequency of 3000 Hz,the duty cycle of 0.1875.