https://www.waferworld.com/post/the-complete-guide-to-doping-in-semiconductors-what-is-it-and-why-is-it-necessary https://www.waferworld.com/post/the-complete-g

https://www.waferworld.com/post/the-complete-guide-to-doping-in-semiconductors-what-is-it-and-why-is-it-necessary https://www.waferworld.com/post/the-complete-guide-to-doping... It's apparently possible for boron doping. I think because phosphorus is bigger than silicium you'll get too many defects in the crystal, while with the smaller boron it is not an issue.