Effect of Radiation on Silicon and Borosilicate Glass

Abstract

A study was made that is logically divided into two parts, both involving radiation damage effects. The first is a study of the effects of neutron and gamma radiation on the dimensions of two borosilicate glasses, pyrex and Hoya SD-2. These two glasses are commonly used as substrates for silicon microelectromechanical (MEMS) devices, and radiation-induced compaction in a substrate can have deleterious effects on device performance. Results are presented for density changes induced in both glasses by neutron irradiation. Pyrex was shown to compact at a rate of (in Gamma p/p per n/sq cm) 8.14 x 1O(exp -20) (thermal) and 1.79 x 1O(sub -20) (fast). The corresponding results for Hoya SD-2 were 2.21 x 1O(sub -21) and 1.71 x 10(sub-21), respectively. On a displacement per atom (dpa) basis, the compaction of the Pyrex was an order of magnitude greater than that of the Hoya SD-2. Our results are the first reported measurement of irradiation-induced densification in Hoya SD-2. The compaction of Pyrex agreed with a previous study. Our results for gamma irradiations were unexpected. Silicon MEMS strain gauges mounted on glass wafers were gamma-irradiated to hundreds of Mrad. Based on expectations from the literature, the Pyrex was supposed to compact to a level easily measurable by the MEMS strain gauges. Almost no substrate compaction registered in the strain gauges, however. It is hypothesized that the anodic bonding process (by which a silicon wafer was bonded to the glass before etching to create the MEMS strain gauges) was responsible for either 1) changing the bulk radiation response of the glass or 2) creating a layer near the bond interface which somehow prevented the MEMS strain gauges from registering the compaction that was occurring in the glass substrate.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 2003
Accession Number
ADA417276

Entities

People

  • Clark L. Allred

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Advanced Electronics
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force
  • Ceramic Materials
  • Crystal Structure
  • Elastic Properties
  • First Principles Calculations
  • Gamma Rays
  • Materials Processing
  • Materials Science
  • Measurement
  • Mechanical Properties
  • Modulus Of Elasticity
  • Molecular Dynamics
  • Nuclear Reactors
  • Point Defects
  • Radiation Effects
  • Resonant Frequency
  • Scattering

Fields of Study

  • Physics

Readers

  • Nuclear and Radiation Engineering.
  • Structural Health Monitoring of Composite Structures.
  • Thin Film Deposition Science.

Technology Areas

  • Microelectronics
  • Microelectronics - Graphene
  • Microelectronics - Microelectromechanical Systems