Mechanical Stress in InP Structures Etched in an Inductively Coupled Plasma Reactor with Ar/Cl2/CH4 Plasma Chemistry

• Published in: Journal of electronic materials 2018-09, Vol.47 (9), p.4964-4969
• Main Authors: Landesman, Jean-Pierre, Cassidy, Daniel T., Fouchier, Marc, Pargon, Erwine, Levallois, Christophe, Mokhtari, Merwan, Jimenez, Juan, Torres, Alfredo
• Format: Article
• Language: English
• Subjects: 17th Conference on Defects-Recognition; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal lattices; Crystal structure; Deformation effects; Electronics and Microelectronics; Emission analysis; Etching; Imaging and Physics in Semiconductors (DRIP XVII); Inductively coupled plasma; Instrumentation; Luminescence; Mapping; Materials research; Materials Science; Methane; Optical and Electronic Materials; Photoluminescence; Plasma chemistry; Plasma etching; Proximity effect (electricity); Separation; Solid State Physics; Stresses; Tensile deformation; Topical Collection: 17th Conference on Defects (DRIP XVII)
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-018-6152-6

We investigated the crystal lattice deformation that can occur during the etching of structures in bulk InP using SiN x hard masks with Ar/Cl 2 /CH 4 chemistries in an inductively coupled plasma reactor. Two techniques were used: degree of polarization (DOP) of the photo-luminescence, which gives information on the state of mechanical stress present in the structures, and spectrally resolved cathodo-luminescence (CL) mapping. This second technique also provides elements on the mechanical stress in the samples through analysis of the spectral shift of the CL intrinsic emission lines. Preliminary DOP mapping experiments have been conducted on the SiN x hard mask patterns without etching the underlying InP. This preliminary study demonstrated the potential of DOP to map mechanical stress quantitatively in the structures. In a second step, InP patterns with various widths between 1 μm and 20 μm, and various depths between 1 μm and 6 μm, were analyzed by the 2 techniques. DOP measurements were made both on the (100) top surface of the samples and on the (110) cleaved cross section. CL measurements were made only from the (100) surface. We observed that inside the etched features, close to the vertical etched walls, there is always some compressive deformation, while it is tensile just outside the etched features. The magnitude of these effects depends on the lateral and depth dimensions of the etched structures, and on the separation between them (the tensile deformation increases between them due to some kind of proximity effect when separation decreases).