An electronic chip including: a plurality of first semiconductor bars of a first conductivity type and of second semiconductor bars of a second conductivity type arranged alternately and contiguously on a region of the first conductivity type; two detection contacts arranged at the ends of each second bar; a circuit for detecting the resistance between the detection contacts of each second bar; insulating trenches extending in the second bars down to a first depth between circuit elements; and insulating walls extending across the entire width of each second bar down to a second depth greater than the first depth.