A method of forming a solar cell having three dimensional junctions created between a conductive substrate having a first conductivity and a conductive layer having an opposite second conductivity comprising the steps of applying the conductive layer on a top surface of the conductive substrate , exposing selective portions of the conductive layer to laser radiations having a wavelength ranging upto 10.6 µm. Due to this laser application, the conductive layer diffuses across a thickness of the conductive substrate in the form of a plurality of channels . The plurality of channels being formed in spaced apart relationship with each other. Thereafter, metal contacts are thermosetted on a bottom surface of the conductive substrate for electrically connecting exposed ends of the plurality of channels.