ACTINIC RADIATION SOURCE HAVING ANODE THAT INCLUDES WINDOW AREA FORMED BY THIN, MONOLITHIC SILICON MEMBRANE

摘要

PURPOSE: An improved thin membrane window that permits an electron beam, originating in a vacuum, to penetrate into medium present on a non-vacuum environment side of the window, and a source of actinic radiation that is simple, durable and reliable, are provided. CONSTITUTION: An actinic radiation source includes an anode(36) upon which an electron beam form a cathode ray gun impinges. The anode includes a window area(52) formed by a silicon membrane. The electron beam upon striking the anode permeates the window area to penetrate into medium surrounding actinic radiation source. A method of making an anode uses a substrate having both a thin first layer(44) and a thicker second layer(46) of single crystal silicon material between which is interposed a layer of etch stop material(48). The second layer is anisotropically etched to the etch stop material to define the electron beam window areas in the first layer. That portion of the etch stop layer exposed by etching through the second layer is then removed. The anode thus fabricated has a thin, monolithic, low-stress and defect-free silicon membrane electron beam window area provided by the first layer of the substrate.