Contact resistivity of TiN on p(+)-Si and n(+)-Si

The accuracy of the derived value of the contact resistivity of TiN on an n(+)-Si solar cell was improved experimentally and compared with values for TiN on a p(+)-Si solar cell. The TiN diffusion barrier was deposited on heavily doped cells by RF sputtering and a layer of silver was laid down over the TiN pad. Electrical measurements were performed on two different test patterns. The contact resistivities for the n and p cells were 0.000015 ohm-sq cm and 0.00028 ohm-sq cm, respectively. The differences were attributed to the barrier height and the surface dopant concentation. The results indicate that the TiN barrier does not degrade in concentrator contigurations of up to 50 suns for the n-type material and up to 100 suns for the p-type material.