Detector with frequency converting coating

US6327284A · kind A · utility

Assignee

• Lambda Physik AG · DE

Inventors

• Uwe Stamm · Göttingen, DE
• Hans-Stephan Albrecht · Göttingen, DE
• Uwe Leinhos · Göttingen, DE
• Wolfgang Zschocke · Göttingen, DE

Key dates

• Filing date: Oct 14, 1998
• Grant date: Dec 4, 2001
• Expiry date: Oct 14, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01J1/58
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An ultraviolet light detection system is provided wherein a dark current background growth rate with total accumulated exposure dose is avoided, and parameters of an ultraviolet radiation source such as an ArF-excimer laser may be monitored without rapid degradation of the signal by the superposition of the dark current background over a desired signal. The invention provides a detector including a light sensitive element having a frequency conversion coating on its surface. The coating is preferably directly on the light sensitive element, absorbing incident ultraviolet light and re-emitting visible light in a direction toward the light sensitive element. The coating minimizes a dark current background that would otherwise appear when incident ultraviolet light impinges directly upon the light sensitive element, and thereby extends a lifetime of the light sensitive element. The detector is useful for detecting a wide range of ultraviolet wavelengths, and is particularly useful in solving the dark current growth rate with total accumulated exposure dose problem associated with detecting incident radiation under 240 nm.