感应耦合等离子体刻蚀InP/InGaAsP二维光子晶体结构的研究

Inductively coupled plasma etching of two-dimensional InP/InGaAsP-based photonic crystal

为实现基于InP/InGaAsP材料的二维光子晶体结构低损伤、高各向异性的干法刻蚀,研究了对InP材料基于Cl2/BCl3气体的感应耦合等离子体刻蚀.从等离子体轰击使衬底升温的角度分析了刻蚀机理,发现离子轰击加热引起的侧蚀与物理溅射在侧壁再沉积之间处于平衡时可以得到高各向异性刻蚀,平衡点将随ICP功率增高而向偏压减小方向移动,从而在近203V偏压下得到陡直的侧壁.在优化气体组分后,成功实现了光子晶体结构高各向异性的低偏压刻蚀.

Inductively coupled plasma （ICP） etching of InP in Cl2/BCl3 gas mixtures is studied in order to achieve low-damage and high-anisotrupy etching of two-dimensional InP/InGaAsP photonic crystal. The etching mechanisms are discussed and the effect of plasma heating on wafer during etching is analyzed . It is shown that the balance between the undercut originating from plasma heating and the redeposition of sputtering on the side-wall is crucial for highly anisotropic etching, and the balance point moves toward lower bias when the ICP power is increased. High aspect-ratio etching at the DC bias of 203 V is obtained. Eventually, photonic crystal structure with nearly 90° side-wall is achieved at low DC bias after optimization of the gas mixture.