Patent ID: 8513104

Claim:
A method of forming a floating junction on a substrate, comprising: providing the substrate doped with boron atoms, the substrate comprising a front surface and a rear surface; depositing a set of masking particles on the rear surface in a set of patterns; heating the substrate in a baking ambient to a first temperature and for a first time period in order to create a particle masking layer; exposing the substrate to a phosphorous deposition ambient at a second temperature and for a second time period, wherein a front surface PSG layer, a front surface phosphorous diffusion, a rear surface PSG layer, and a rear surface phosphorous diffusion are formed, and wherein a first phosphorous dopant surface concentration in the substrate proximate to the set of patterns is less than a second dopant surface concentration in the substrate not proximate to the set of patterns; exposing the substrate to a set of etchants for a third time period, wherein the front surface PSG layer and the rear surface PSG layer are substantially removed; depositing a front surface SiN x layer and a rear surface SiN x layer; and forming a rear metal contact on the rear surface through the rear surface SiN x layer proximate to the set of patterns.