An example of fluorine doping in a mixed magnesium-zinc oxide is reported in the open-access article by [Liu et al.[1]](https://doi.org/10.1038/srep15516). The excerpt below from the abstract indicates the effectiveness of fluorine as an $n$-type dopant. The oxide actually has a wurtzite rather than a rocksalt crystal structure; presumably the tetrahedral rather than octahedral coordination in the wurtzite structure facilitates diffusion of the large fluoride ions into the crystal.
Fluorine dopants were demonstrated to be effective donors in $\ce{Mg_{0.51}Zn_{0.49}O}$ single crystal film having a solar-blind $4.43$ eV bandgap, with an average concentration of $1.0×10^{19}$ F/cm$^3$. The dramatically increased carrier concentration ($2.85×10^{17}$ cm$^{−3}$ vs $\sim10^{14}$ cm$^{−3}$) and decreased resistivity ($129$ Ω•cm vs $\sim10^6$ Ω•cm) indicate that the electrical properties of semi-insulating $\ce{Mg_{0.51}Zn_{0.49}O}$ film can be delicately regulated by $\ce{F}$ doping.
Reference
1. Lishu Liu, Zengxia Mei, Yaonan Hou, Huili Liang, Alexander Azarov, Vishnukanthan Venkatachalapathy, Andrej Kuznetsov & Xiaolong Du. "Fluorine doping: a feasible solution to enhancing the conductivity of high-resistance wide bandgap $\ce{Mg_{0.51}Zn_{0.49}O}$ active components". Sci Rep 5, 15516 (2015). https://doi.org/10.1038/srep15516