Methods of forming a high efficiency solar cell with a localized back surface field

A method of forming a high efficiency solar cell, comprising steps of:

• (a) providing a doped silicon substrate, the substrate comprising a front surface and a rear surface;
• (b) depositing an ink on the rear surface in a pattern, the ink comprising a p-type dopant and a solvent;
• (c) heating the silicon substrate in a baking ambient to a first temperature and for a first time period in order to remove residual solvent from the deposited ink;
• (d) heating the silicon substrate in a diffusion ambient to a second temperature and for a second time period in order to diffuse the p-type dopant into the rear surface to form a rear p+ diffusion area on the rear surface;
• (e) exposing the silicon substrate to a phosphorous deposition ambient at a third temperature for a third time period, wherein a front PSG layer and a front phosphorous diffusion layer are formed on the front surface, and wherein a rear PSG layer and a rear phosphorous diffusion layer are formed on the rear surface;
• (f) exposing the silicon substrate to an etchant for a third time period, wherein the front PSG layer is removed, and wherein the rear PSG layer is removed;
• (g) depositing a front anti-reflective layer on the front surface and a rear passivation layer on the rear surface;
• and
• (h) forming a front metal electrode on the front surface in ohmic contact with the front phosphorous diffusion layer through the front anti-reflective layer and a rear metal electrode on the rear surface through the rear passivation layer, the rear metal electrode being formed on the rear p+ diffusion area on the rear surface.