High sensitivity charge amplifier for ion beam uniformity monitor

Patent · Mon Jan 01 00:00:00 EST 2001

OSTI ID:873990

Johnson, Gary W ^[1]

---

1. Livermore, CA

An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 6288402
• OSTI ID: 873990
• Country of Publication: United States
• Language: English

Related Subjects

sensitivity
charge
amplifier
beam
uniformity
monitor
currents
high-sensitivity
bias
compensation
assess
raster-scanned
implanter
utilizes
faraday
cups
placed
geometric
corners
target
current
cup
integrated
respect
time
measuring
accumulated
dose
coulombs
comparing
corner
qualitative
assessment
knowledge
relative
flux
areal
obtained
charge amplifier
beam current
faraday cup
beam uniformity
beam currents
uniformity monitor
sensitivity charge
beam monitor
/250/