Hydrogen free diborane ion source using 500 MHz RF discharge

A large area diborane ion source which can make the hydrogen ion components negligibly small is developed for the very low energy implantation. Since the ionization energy of diborane is considerably lower than that of hydrogen, we may diminish the hydrogen components by lowering the electron energy in the source plasma. With a Langmuir probe measurement, the relationships between the electron energy and the adjustable discharge parameters such as the radio frequency, RF power, magnetic field configuration have been widely examined. Using the 500 MHz radio frequency and optimizing the other parameters, we have proved experimentally that the component of the hydrogen ions becomes less than 0.1% with respect to the diborane ions