Instabilities and related drawbacks that arise when interruptions of a perimetral high voltage ring extension implanted regions (RHV) of a main junction (P_tub 1, (P_tub2, . . . ) of an integrated device must be realized may be effectively prevented. This important result is achieved by an extremely simple expedient: whenever an interruption (I) of the high voltage ring extension must be created, it is not realized straight across it along a common orthogonal direction to the perimetral implanted region, on the contrary, the narrow interruption is defined obliquely or slantingly across the width of the perimetral high voltage ring extension. In case of a straight interruption, the angle of slant (α) may be generally comprises between 30 and 60 degrees and more preferably is 45 degrees or close to it. Naturally, the narrow interruption is created by masking it from dopant implantation when realizing the perimetral high voltage ring extension region.