Patent ID: 6429037
Filing Date: 2002-08-06
Classification: H01L,Y02E,Y02P

Abstract:
A self aligning method of forming contact metallization in a solar cell, the method including the steps of:a) on a surface of a semiconductor substrate of a first dopant type, forming a continuous layer of dopant source material of a second dopant type of opposite dopant polarity to that of the first dopant type, the source material being selected to also act as a surface passivation layer and a metallization pattern mask, or to be modifiable in situ to act as a surface passivation layer and a metallization pattern mask; b) thermally treating the dopant source material and the semiconductor surface carrying the dopant source, whereby a surface region of the second dopant type is formed in the semiconductor material, the first and second doped semiconductor types forming a p-n junction beneath the surface of the semiconductor substrate; c) locally heating the dopant source material and the underlying semiconductor surface, by scanning a beam of a laser over the area of the device where metallization is to be applied, to cause melting of the surface region in zones where metallization is required to contact to the surface region whereby the melted zones of the semiconductor surface region are more heavily doped from the dopant source material and the overlying dopant source material is disrupted to expose the more heavily doped surface zones, thereby simultaneously patterning the source material; d) forming metallization over the heavily doped surface zones such that connection to the surface region of the semiconductor material is made to the heavily doped surface zones through the disruption in the layer of dopant source material.