GaN/SiO_2刻蚀选择比的研究

Reserch on the Etching Selectivity of GaN/SiO_2

在干法刻蚀GaN时使用SiO2作为掩蔽物,为了在较快的GaN刻蚀速率下获得良好的GaN/SiO2刻蚀选择比,使用电感耦合等离子刻蚀机(ICP),运用Cl2和Ar作为刻蚀气体,改变ICP功率、直流自偏压、气体总流量、气体组分等工艺条件,并讨论了这些因素对GaN/SiO2刻蚀选择比以及对GaN刻蚀速率的影响。实验结果获得了GaN在刻蚀速率为165nm/min时的GaN/SiO2选择比为8∶1。设备验收时GaN刻蚀速率为70nm/min,GaN/SiO2选择比为3.5∶1,可以应用于实际生产。

A Cl2/Ar inductively-coupled plasma （ICP） was used to etch GaN, using SiO2 as the barrier layer. The etching selectivity of GaN/SiO2 was improved from 3.5 to 8 by changing the ICP power, DC bias, total flow rate, and the ratio of Cl2. The effect of the factors above on the etching selectivity of GaN/SiO2 and the etching rate of GaN was discussed. Experimental results indicate that the selectivity of GaN/SiO2 can reach to 8 while the etching rate of GaN is 165 nm/min. The etching rate of GaN is 70 nm/min and the selectivity is 3.5 during the reception test. It fits to the practical production.