Charge amplifier with bias compensation
US6437342B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 2001 |
| Grant date | Aug 20, 2002 |
| Priority date | — |
| Expiry date | May 29, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31703
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.