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Doping of semiconductors is one of the most important steps in the fabrication of integrated circuits. Generally, Group IV elements such as boron, arsenic, phosphorus and gallium are used to dope Group IV p-type silicon wafer. Boron is especially preferred because it diffuses at a rate that makes it possible to control junction depths. It also has a lower energy band gap than phosphorus, allowing it to more easily bond with the atomic sites in the silicon.

In the present work, a new texturizing process for boron doped mc-Silicon wafers is presented. It involves the decomposition of a boron precursor in two stages. The first stage produces the oxide compound B2O3, which is deposited on the surface of the silicon. The second stage carries out the diffusion of boron atoms in the silicon, which results in local modification of its semi-conductive properties.

The characterization of the modified wafers was carried out by using HRTEM post-treatment and SIMS. It showed that the boron doping caused significant changes in the optical properties of the as-cut mc-Silicon, with a notable decrease of the reflectance.

To evaluate the influence of the boron doping on the minority carrier diffusion length, a simulation model was used. This consists of a set of equations describing the evolution of the minority carrier lifetime as a function of the boron concentration in the silicon. It is based on the fact that in a perfect crystal, dopant impurities create energy states close to the conduction band. As a result, they capture electrons in the semiconductor. This is known as the ‘donor effect’ and produces a ‘p-type’ semiconductor.