Plasma doping method and apparatus thereof
In a plasma torch unit, a conductor rod having a spiral shape is disposed inside a quartz pipe having a surface coated with boron glass, and a brass block is disposed on the periphery thereof. While a gas is being supplied into a cylindrical chamber, a high-frequency power is supplied to the conductor rod and a plasma is generated in the cylindrical chamber, so that a base material is irradiated with the plasma.
1. A plasma doping apparatus comprising:
a casing that forms a cylindrical chamber having a slit-shaped opening portion, with a longitudinal direction of the opening portion and a longitudinal direction of the cylindrical chamber being set in parallel with each other;
a gas supply device that supplies a gas into the chamber;
a coil for use in generating a high-frequency electromagnetic field in the chamber;
a high-frequency power supply for supplying a high-frequency power to the coil;
a base material placing table disposed to face the opening portion, on which a base material is placed;
a moving device that relatively moves the chamber and the base material placing table relative to each other in a direction perpendicular to a longitudinal direction of the opening portion; and
an elongated member provided at least at one portion of an inner wall surface of the cylindrical chamber, or between the cylindrical chamber and the base material placing table, the member extending in the longitudinal direction of the cylindrical chamber, and being made of a material containing atoms or molecules to be doped, wherein
the atoms or molecules are doped in a semiconductor configuring a surface of the base material.
2. The plasma doping apparatus according to claim 1 , wherein the coil is a solenoid coil, and an extending direction of the coil and the longitudinal direction of the opening portion are set in parallel with each other.
3. The plasma doping apparatus according to claim 1 , wherein
the coil is configured by connecting a plurality of conductor rods disposed in parallel with the longitudinal direction of the cylindrical chamber with one another, by using a conductor link disposed perpendicularly to the longitudinal direction of the cylindrical chamber,
the conductor rods are inserted into dielectric pipes, and
one portions of the dielectric pipes are disposed so as to be exposed to a space inside the cylindrical chamber.
4. The plasma doping apparatus according to claim 1 , wherein one portion of an inner wall surface of the cylindrical chamber is made of a material containing the atoms or molecules, another portion different from the one portion of the inner wall surface of the cylindrical chamber is made of a material containing other atoms or molecules different from the atoms or molecules.
5. The plasma doping apparatus according to claim 1 , wherein substantially an entire portion of the inner wall surface of the cylindrical chamber is made of a material containing the atoms or molecules.
6. The plasma doping apparatus according to claim 1 , wherein, by supplying the high-frequency power to the coil from the high-frequency power supply, the atoms or molecules are generated from a solid substance by sublimation caused by heat of a plasma or by chemical etching caused by activator species in the plasma, and by irradiating the base material whose surface is a semiconductor with the plasma, the atoms or molecules are doped in the semiconductor and the semiconductor is simultaneously heated to an activatable temperature so as to be activated.