High-speed diamond photoconductors: a solution for high rep-rate deep-UV laser applications

Beam monitoring of excimer lasers operating at high powers in the deep ultr a-violet (DUV) is becoming increasingly important, due to the rapid prolife ration of these systems in micromachining, photolithography, and other area s of industrial interest. This task requires radiation-hard detectors able to operate effectively for extended periods at high laser rep-rates. DUV-vi sible-blind photoconductors can be fabricated on polycrystalline CVD diamon d, a material that is intrinsically radiation-hard and visible-blind. Howev er, the performance of detectors fabricated on as-grown material is insuffi cient to meet the requirements of many excimer laser applications. In this paper, we show that sequentially applied post-growth treatments can progres sively change both the gain and speed of these devices. Charge-sensitive de ep-level transient spectroscopy (Q-DLTS) and transient photoconductivity (T PC) has been used to study the effect of these treatments on the defect str ucture of our thin-film diamond detector material, For the first time, we r eport the successful operation of a diamond photoconductive device with lin ear bias and fluence-response characteristics at more than 1 kHz at 193 nm. (C) 2001 Elsevier Science B.V. All rights reserved.