A method of forming a semiconductor device comprises forming a first fin on a substrate, depositing an insulator layer on the substrate adjacent to the first fin, removing a first portion of the insulator layer to expose a first portion of a sidewall of the first fin, depositing a layer of spacer material over the first portion of the sidewall of the first fin, removing a second portion of the insulator layer to expose a second portion of the sidewall of the first fin, depositing a first glass layer including a first doping agent over the exposed second portion of the sidewall of the first fin, and performing a first annealing process to drive the first doping agent into the first fin.