Plasma doping method and plasma doping apparatus

• US 20070176124A1
• Filed: 03/30/2007
• Published: 08/02/2007
• Est. Priority Date: 05/12/2005
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ito, Hiroyuki, Okumura, Tomohiro, Okashita, Katsumi, Mizuno, Bunji, Sasaki, Yuichiro
• Application Number:
  US11/730,244
• Publication Number:
  US 20070176124A1
• Time in Patent Office: Days
• US Class Current: 250/492.210
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: H01J 37/32412 Plasma immersion ion implantation
• CPC Class Codes: H01L 21/2236 from or into a plasma phase

Abstract

Disclosed is a plasma doping method that, even though a plasma doping treatment is repeated, can make a dose from a film to a silicon substrate uniform for each time. According to an embodiment of the invention, there is provided a plasma doping method that places a sample on a sample electrode in a vacuum chamber, generates plasma in the vacuum chamber, and causes impurity ions in the plasma to collide against a surface of the sample so as to form an impurity doped layer in the surface of the sample. The plasma doping method includes a maintenance step of preparing the vacuum chamber having a film containing an impurity formed on an inner wall thereof such that, when the film containing the impurity fixed to the inner wall of the vacuum chamber is attacked by ions in the plasma, the amount of an impurity to be doped into the surface of the sample by sputtering is not changed even though the plasma containing the impurity ions is repeatedly generated in the vacuum chamber, a step of placing the sample on the sample electrode, and a step of irradiating the plasma containing the impurity ions so as to implant the impurity ions into the sample, and doping the impurity into the sample by sputtering from the film containing the impurity fixed to the inner wall of the vacuum chamber.

Claims

1-22. -22. (canceled)

23. A silicon substrate with a diameter of 300 mm in which boron is introduced to a surface thereof by a plasma doping process using successive plasma containing the boron,

wherein the introduced boron has such a profile that a depth at which a boron concentration is 5×

10 ¹⁸cm<sup>−

3</sup> is in the range of 7 to 15.5 nm,

wherein the abruptness of the depth profile of boron is in the range of 1.5 to 3 nm/decade in a distance in which the boron concentration is lowered from 1×

10¹⁹ cm<sup>−

3</sup> to 1×

10¹⁸ cm<sup>−

3</sup>; and

wherein a standard deviation of a boron dose on surfaces of the silicon substrate other than a portion in 3 mm from the edge thereof is 2% or less.

25. The silicon substrate according to claim 23, wherein the abruptness of the depth profile of boron is in the range of 1.7 to 2.7 nm/decade.

24. A silicon substrate with a diameter of 300 mm in which a boron introduced layer is formed in a surface thereof by a plasma doping process using successive plasma containing boron,

wherein the boron introducing layer is formed by generating plasma containing boron in a vacuum vessel having an inner wall on which a film containing boron is formed,

wherein the introduced boron has such a profile that a depth at which a boron concentration is 5×

10¹⁸ cm<sup>−

3</sup> is in the range of 7 to 15.5 nm, wherein a abruptness of the boron depth is in the range of 1.5 to 3 nm/decade in a distance in which the boron concentration is lowered from 1×

10¹⁹ cm<sup>−

3</sup> to 1×

10¹⁸ cm<sup>−

3</sup>; and

wherein a standard deviation of a boron dose on surfaces of the silicon substrate other than a portion is 3 mm from the edge thereof is 2% or less.

26. The silicon substrate according to claim 24, wherein the abruptness of the depth profile of boron is in the range of 1.7 to 2.7 nm/decade.

27. A plasma doping apparatus for forming an impurity introduced layer on a processing substrate, the plasma doping apparatus comprising:

a vacuum vessel having an inner wall on which a film containing a first impurity is formed;

a sample support which is surrounded by the inner wall of the vacuum vessel and on which the processing substrate is placed;

a coil and antenna provided opposite to the sample support and serving as a plasma source;

a first high-frequency power supply supplying a high frequency power to the coil and antenna; and

a second high-frequency power supply providing a high-frequency power to the sample support,

wherein a gas containing the first impurity are introduced into the vacuum vessel to generate successive plasma by the coil and antenna, the first high-frequency power supply, and the second high-frequency power supply.