Anisotropic Chemical Etching of III—V Crystals Dissolution Slowness Surface and Application to GaAs

The analytical equation for the dissolution slowness surface of III–V crystals that belong to point group4¯3 mis derived using a tensorial analysis of the anisotropic chemical dissolution. The role played by orientation functions in the generation of the dissolution slowness extrema is discussed. Four different databases composed of dissolution constants are proposed. The final shape of cross-sectional dissolution profiles etched in differently oriented GaAs surfaces is analyzed and compared with published experimental results. Finally etching shapes of micromachined membranes and mesa are derived showing that the anisotropy for the GaAs crystal is probably of type 2 rather than of type 1.

Some Investigations on the Anisotropy of the Chemical Etching of(h k 0)and(h h I)Silicon Plates in a NaOH 35% Solution. Part III: Determination of a Database for the Simulator Tensosim and Prediction of 2D Etching Shapes

The simulation of 2D etching shapes such as surface profiles and out-of-roundness profiles related to various (h k 0) and (h h l) silicon plates or cross-sections is studied. The theoretical basis of the simulation is presented. The database for the simulator TENSOSIM is determined from a systematic analysis of experimental 2D etching shapes. Emphasis is placed on difficulties encountered in the determination procedure. Theoretical 2D etching shapes are compared with experimental shapes. A correlation between polar plots of the dissolution slowness and corresponding theoretical shapes is established. So we can conclude that the accuracy of the proposed database is sufficient for the simulation of 2D etching shapes.

Some Investigations on the Anisotropy of the Chemical Etching of (hk0) and (hhl) Silicon Plates in a NaOH 35% Solution. Part I: 2D Etching Shapes

In this paper a study of the anisotropic dissolution of (hk0) and (hhl) silicon plates in a NaOH 35% solution is undertaken. Effects of orientation on firstly, the geometrical features of etched surfaces and secondly, on the cross-sectional shape of starting circular plates are systematically investigated. Conclusions of practical interest on the roughness of etched (hk0) and (hhl) planes are drawn. 2D etching shapes are then analysed in terms of the tensorial model for the anisotropic dissolution and of dissolution criteria. Finally a comparative analysis of results related on the one hand, to 2D surface profiles and on the other, to out-of-roundness profiles is made. This comparison shows that shapes observed for profilometry traces agree with theoretical shapes as derived when we use the resemblance in shapes between out-of-roundness profiles and polar diagrams of the dissolution slowness.

Chemical Etching of {hk0} Silicon Plates in EDP Part I: Experiments and Comparison with TMAH

This paper deals with the anisotropic chemical etching of various silicon plates etched in EDP. Changes with orientation in geometrical features of etched surface and in the etching shape of starting circular sections are systematically investigated. These etching shapes are compared with shapes produced by etching in KOH and TMAH solutions; This experimental study allows us to determine the dissolution slowness surface for the EDP solution and to investigate the real influence of the etchant on two dimensional and three dimensional etching shapes.