In a first standby state, the reception quality of a signal from a system which has established synchronization is detected. The device may be provided at any point along the riser ensuring the establishment of an area of physical and visual contact directly over the surface of the tensile armour of the riser for the installation of equipment for analysis, which area permits further accesses without destroying the sealing of the chamber there formed. The solution is ionized to provide ionized molecules of the solvent and molecules of the macro-molecular species. Finally, a patterned second resist layer is formed on the cured first resist layer. The difference between the maximum value and minimum value of the lattice distortions of a GaAs single crystal at a normal temperature is set to at most 4105, and the density of Si atoms contained in the GaAs single crystal is set to at most 11016 cm3, whereby the characteristics of semiconductor elements whose parent material is the GaAs single crystal can be made uniform.