Melting of silicon surfaces by high-power pulsed microwave radiation

Journal Article · Thu Sep 15 00:00:00 EDT 1988 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.341543· OSTI ID:6926488

James, R B; Bolton, P R; Alvarez, R A; Christie, W H; Valiga, R E

We have measured the microwave-induced melting and damage to the near-surface region of arsenic-implanted silicon for 1--2 ..mu..s pulses at a frequency of 2.856 GHz and an incident pulse power of up to 9 MW. Rectangular samples were irradiated by single-pass TE/sub 10/ traveling wave pulses inside a WR-284 waveguide, and time-resolved in situ and post-irradiation studies were performed to characterize the material modifications induced by the microwave pulses. The test chamber where the specimens were irradiated was either evacuated to a pressure of 10/sup -7/--10/sup -6/ Torr or filled with a 30-psig pressure of Freon-12. Incident, transmitted, and reflected powers were monitored with directional couplers and fast diodes. The results of the time-resolved optical measurements for samples irradiated in vacuum show that melting of the near-surface region occurs for pulse powers exceeding 3 MW, and that the surface melting is accompanied by a large increase in the reflected microwave power. The onset of the enhanced reflectivity is measured at an earlier time as the microwave power is increased, and once the abrupt increase in the reflectivity is observed, it persists throughout the remainder of the pulse. Simultaneous with the onset of surface damage, we observe a large enhancement in the emission of light from the sample. Results are presented for the temporal behavior and spectral components of the fluorescence as a function of the incident microwave power. The gas pressure in the test cell was also monitored, and a large increase in the gas pressure was detected at the same pulse power as the threshold for the sudden increase in the microwave reflectivity.

• Research Organization: Sandia National Laboratories, Livermore, California 94550
• OSTI ID: 6926488
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 64:6; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360605* -- Materials-- Radiation Effects
656003 -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ELECTROMAGNETIC RADIATION
ELEMENTS
LASER RADIATION
MELTING
MICROWAVE RADIATION
PHASE TRANSFORMATIONS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
RADIATIONS
SEMIMETALS
SILICON