Ion source and ion implantation apparatus

An ion source which extracts, in a Z direction, a ribbon-shaped ion beam having a dimension in a Y direction greater than that in a X direction wherein the X direction, the Y direction and the Z direction are substantially orthogonal at one point, the ion source comprising:

• a plasma generating chamber into which a material gas is introduced to generate plasma thereinside;
• a plasma electrode which is disposed near the end of the plasma generating chamber in the Z direction and has an ion extracting port extending in the Y direction;
• a plurality of cathodes which emits electrons into the plasma generating chamber to cause an electrical discharge inside the plasma generating chamber to ionize the material gas, thereby generating the plasma, the cathodes being disposed inside the plasma generating chamber on the side opposite to the plasma electrode, the cathodes being arranged in a plurality of stages along the Y direction;
• and
• a magnetic coil which is disposed outside the plasma generating chamber to generate magnetic fields along the Z direction inside the plasma generating chamber and also at a domain containing the plurality of cathodes.