Amorphous silicon-based microchannel plates

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2012-12, Vol.695, p.74-77
• Main Authors: Franco, Andrea, Riesen, Yannick, Wyrsch, Nicolas, Dunand, Sylvain, Powolny, François, Jarron, Pierre, Ballif, Christophe
• Format: Article
• Language: English
• Subjects: Amorphous silicon; Microchannel plates; Plasma enhanced chemical vapor deposition (PECVD)
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2011.11.089

Microchannel plates (MCP) based on hydrogenated amorphous silicon (a-Si:H) were recently introduced to overcome some of the limitations of crystalline silicon and glass MCP. The typical thickness of a-Si:H based MCPs (AMCP) ranges between 80 and 100μm and the micromachining of the channels is realized by deep reactive ion etching (DRIE). Advantages and issues regarding the fabrication process are presented and discussed. Electron amplification is demonstrated and analyzed using Electron Beam Induced Current (EBIC) technique. The gain increases as a function of the bias voltage, limited to −340V on account of high leakage currents across the structure. EBIC maps on 10° tilted samples confirm that the device active area extend to the entire channel opening. AMCP characterization with the electron beam shows gain saturation and signal quenching which depends on the effectiveness of the charge replenishment in the channel walls.