[en] P-type transition metal dichalcogenides (TMDCs) field-effect transistor (FET) with high performance is fundamental for the development of 2D electronic and optoelectronic devices. We achieve the effective p-type doping using toroidal-magnetic-field (TMF) controlled oxygen plasma on the six-layer MoS₂. The bottom-gated MoS₂ FET shows a record current on-off ratio of 10⁷, a hole mobility of 115.2 cm² V⁻¹ s⁻¹ and a subthreshold swing of 137 mV dec⁻¹ at room temperature. The high performance is attributed to the negligible lattice defects and high substitutional rate through restricting the energy of oxygen ions, which are demonstrated by Raman spectroscopy, photoluminescence spectroscopy and x-ray photoelectron spectroscopy. The excellent p-type conduction is also beneficial from enhancing the ratio of ions in oxygen plasma by the TMF. First-principle calculations validate that ions lead to a shallow acceptor level at 42.16 meV above the valance band maximum and extracting 1.0 electron from MoS₂ lattice. These findings provide a scheme for realizing 2D integrated circuit and excellent optoelectronic devices using MoS₂ and other homogeneous TMDCs. (paper)