Ion implantation and surface processing method and apparatus

A pulse modulator for applying electrical pulses to an object for implantation with ions from a plasma in a plasma source ion implantation apparatus, comprising:

• first power source means for generating a first electrical potential;
• first capacitor means connected in circuit with the first power source means for charging therefrom;
• first plasma switch means connected in circuit for causing the first capacitor means to periodically discharge into and thereby apply first electrical pulses to the object;
• the first power source means, first capacitor means and first plasma switch means being connected in circuit to apply the first electrical pulses to the object with a negative polarity;
• second power source means for generating a second electrical potential;
• second capacitor means connected in circuit with the second power source means for charging therefrom;
• and
• second plasma switch means connected in circuit for causing the second capacitor means to periodically discharge into the object and thereby apply second electrical pulses to the object;
• the second power source means, second capacitor means and second plasma switch means being connected in circuit to apply the second electrical pulses to the object with a positive polarity.

A bipolar pulse modulator for individually applying electric pulses to an object for implantation with ions or for surface processing with electrons from a plasma in a plasma source ion implantation apparatus, comprising:

• negative power source means;
• first switch means connected in circuit for periodically electrically connecting the negative power source means to the object so that negative pulses are applied to the object;
• positive power source means;
• and
• second switch means connected in circuit for periodically electrically connecting the positive power source means to the object so that positive pulses are applied to the object during periods when the negative power source means is not connected to the object.

A bipolar pulse modulator for individually applying electric pulses to an object for implantation with ions or for surface processing with electrons for a plasma in a plasma source ion implantation apparatus, comprising:

• negative power source means;
• first switch means connected in circuit for periodically electrically connecting the negative power source means to the object so that negative pulses are applied to the object;
• positive power source means;
• and
• second switch means connected in circuit for periodically electrically connecting the positive power source means to the object so that positive pulses are applied to the object during periods when the negative power source means is not connected to the object, and
• further comprising pulse transformer means connected in circuit between the negative and positive power source means and the object for stepping up the voltage of the negative and positive electrical pulses applied to the object respectively.

A method of applying electrical pulses to an object for surface processing with electrons or implantation with ions from a plasma in a plasma source ion implantation apparatus, comprising:

• providing negative power source means;
• periodically applying negative pulses to the object using a first switch connected to the negative power source means to implant ions into the object;
• providing positive power source means;
• and
• applying positive pulses to the object using a second switch connected to the positive power source means to periodically apply the positive pulses alternating with and between the negative pulses to accelerate electrons into the object.

An ion implantation apparatus comprising:

• a container for enclosing an object to be implanted;
• plasma generator means for generating a plasma which surrounds the object in the container;
• and
• a pulse modulator for applying positive electrical pulses to the object which cause electrons to be accelerated from the plasma into the object, the pulse modulator including:
• power source means for generating an electrical potential;
• capacitor means connected in circuit with the power source means for charging therefrom;
• and
• plasma switch means connected in circuit for causing the capacitor means to periodically discharge into and thereby apply said positive electrical pulses into the object, and
• further comprising pulse transformer means connected in circuit between the capacitor means and the object for stepping up the voltage of the electrical pulses applied to the object.