Research on silicon microchannel array oxidation insulation technology and stress issues

Abstract

Microchannel plate is widely used in the field of low light level night vision, photomultiplier, tubes, X-ray enhancer and so on. In order to meet the requirement of microchannel plate electron multiplier, we used the method of thermal oxidation to produce a thin film of silicon dioxide which could play a role in electric insulation. Silicon dioxide film has a high breakdown voltage, it can satisfy the high breakdown voltage requirements of electron multiplier. We should find the reasonable parameter values and preparation process in the oxidation so that the thickness and uniformity of the silicon dioxide layer would meet requirement. This article has been focused on researching and analyzing of the problem of oxide insulation and thermal stress in the process of production of silicon dioxide film. In this experiment, dry oxygen and wet oxygen were carried out respectively for 8 hours. The thickness of dry oxygen silicon dioxide films was 458 nm and wet oxygen silicon dioxide films was 1.4 μm. Under these conditions, the silicon microchannel is uniformity and neat, meanwhile the insulating layer's breakdown voltage was measured at 450 V after the wet oxygen oxidation. By using ANSYS finite element software, we analyze the thermal stress, which came from the microchannel oxygen processes, under the conditions of which ambient temperature was 27 ℃ and porosity was 64%, we simulated the thermal stress in the temperature of 1200 ℃ and 1000 ℃, finally we got the maximum equivalent thermal stress of 472 MPa and 403 MPa respectively. The higher thermal stress area was spread over Si-SiO₂ interface, by simulate conditions 50% porosity silicon microchannel sample was selected for simulation analysis at 1100 ℃, we got the maximum equivalent thermal stress of 472 MPa, Thermal stress is the minimum value of 410 MPa.