A planar power-switching electronic component with high electron mobility, comprising a plurality of elementary transistors on a substrate coated with a semi-conductive layer, said elementary transistors each comprising three electrodes (S, G, D) on the surface of said semi-conductive layer, said component having an upper face, on the semi-conductive side, and a rear face, on the opposite side, wherein each of said elementary transistors has a closed circular or polygonal topology, with: • on the semi-conductive side, a first electrode respectively forming a circular or polygonal ring; • at the centre of said ring, a second electrode (S, D) respectively forming a solid disc or polygon not abutting the ring and connected to a rear connection plane by means of vias; and • surrounding the ring, a third electrode (D, S) occupying the remaining surface of the semi-conductive layer and forming any surface not abutting said ring, and wherein: • an insulator is deposited on the semi-conductive side of the component, outside of a second connection pad, its flat surface defining said upper face, an opening being made to connect said first electrode; • said first electrode is connected to an upper connection plane located on the upper face, said plane being made up of a first metallisation layer applied to said upper face except on the second pad, so as to form a continuous connection plane interconnecting said first electrodes, said upper connection plane being fed with electric current through a first metallic pad; and • a rear connection plane is located on the side of the rear face and is made up of a second metallisation layer applied to said rear face, so as to form a continuous ground plane; and • a continuous intermediate connection plane (D, S) located between the rear connection plane and the upper connection plane forms said third electrode (D, S), said intermediate connection plane being fed with electric current through a second metallic pad. • on the semi-conductive side, a first electrode respectively forming a circular or polygonal ring; • at the centre of said ring, a second electrode (S, D) respectively forming a solid disc or polygon not abutting the ring and connected to a rear connection plane by means of vias; and • surrounding the ring, a third electrode (D, S) occupying the remaining surface of the semi-conductive layer and forming any surface not abutting said ring, • an insulator is deposited on the semi-conductive side of the component, outside of a second connection pad, its flat surface defining said upper face, an opening being made to connect said first electrode; • said first electrode is connected to an upper connection plane located on the upper face, said plane being made up of a first metallisation layer applied to said upper face except on the second pad, so as to form a continuous connection plane interconnecting said first electrodes, said upper connection plane being fed with electric current through a first metallic pad; and • a rear connection plane is located on the side of the rear face and is made up of a second metallisation layer applied to said rear face, so as to form a continuous ground plane; and • a continuous intermediate connection plane (D, S) located between the rear connection plane and the upper connection plane forms said third electrode (D, S), said intermediate connection plane being fed with electric current through a second metallic pad.