We present differential sputter yield measurements of boron nitride due to bombardment by xenon ions. A four-grid ion optics system is used to achieve a collimated ion beam at low energy (<100 eV). A quartz crystal microbalance is used to measure differential sputter yield profiles of condensable components from which total sputter yields can also be determined. We report total and differential sputter yields of three grades of boron nitride due to bombardment by xenon ions for ion energies in the range 60–500 eV and ion incidence angles of 0°, 15°, 30° and 45° from the normal. Comparisons with published values are made where possible.

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/PRS SPONSOR/MONITOR'S Pollux Drive NUMBER(S)Edwards AFB CA 93524-7048 AFRL-PR-ED-TP-2007-406 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited (PA #07939A). ABSTRACTWe present results of differential sputter yield measurements of HBC and HBR grades of boron nitride due to bombardment by xenon ions. Total sputter yield measurements are made using a weight loss approach. Differential sputter yield measurements (of condensable components) are made using a quartz crystal microbalance (QCM). The QCM measurement allows full angular resolution, i.e. differential sputtering yield measurements are measured as a function of both polar angle and azimuthal angle. Measured profiles are presented for 100, 250, 350 and 500 eV Xe+ bombardment at 0º, 15º, 30º and 45º angles of incidence. We fit the measured profiles with Modified Zhang expressions using two free parameters: the total sputter yield, Y, and characteristic energy E*. Sputtering of HBC versus HBR grades of BN is compared, as is results of sputter measurements from the weight loss versus QCM approaches. Finally, effects of sample moisture absorption are considered. Abstract: We present results of differential sputter yield measurements of HBC and HBR grades of boron nitride due to bombardment by xenon ions. Total sputter yield measurements are made using a weight loss approach. Differential sputter yield measurements (of condensable components) are made using a quartz crystal microbalance (QCM). The QCM measurement allows full angular resolution, i.e. differential sputtering yield measurements are measured as a function of both polar angle and azimuthal angle. Measured profiles are presented for 100, 250, 350 and 500 eV Xe+ bombardment at 0º, 15º, 30º and 45º angles of incidence. We fit the measured profiles with Modified Zhang expressions using two free parameters: the total sputter yield, Y, and characteristic energy E*. Sputtering of HBC versus HBR grades of BN is compared, a...

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. ions. A four-grid system is used to achieve a collimated beam at low energy (<100 eV). A weight loss approach is used to measure total sputter yields and a quartz crystal microbalance (QCM) is used to measure differential sputter yield profiles of condensable components. Integration of the QCM profiles also gives total sputter yields of condensable components. We report initial results of total and differential sputter yield measurements of three grades of boron nitride due to bombardment by xenon ions with ion energies in the range of 60-250 eV and at ion incidence angles of 0, 15, and 45 degrees from normal. Comparison with past measurement results are made where possible. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON 1Lt Michael Gorrilla a. REPORT Unclassified b. ABSTRACT Unclassified c. THIS PAGE Unclassified SAR 61 19b. TELEPHONE NUMBER (include area code) N/A Standard Form 298 (Rev. 8-98)We describe the development of an experimental apparatus geared towards measurement of boron nitride sputtering by low energy ions. A four-grid system is used to achieve a collimated beam at low energy (<100 eV). A weight loss approach is used to measure total sputter yields and a quartz crystal microbalance (QCM) is used to measure differential sputter yield profiles of condensable components. Integration of the QCM profiles also gives total sputter yields of condensable components. We report initial results of total and differential sputter yield measurements of three grades of boron nitride due to bombardment by xenon ions with ion energies in the range of 60-250 eV and at ion incidence angles of 0, 15, and 45 degrees from normal. Comparison with past measurement results are made where possible.

We present a quartz crystal microbalance-based system for high sensitivity differential sputter yield measurements of different target materials due to ion bombardment. The differential sputter yields can be integrated to find total yields. Possible ion beam conditions include ion energies in the range of 30-350 eV and incidence angles of 0 degrees-70 degrees from normal. A four-grid ion optics system is used to achieve a collimated ion beam at low energy (<100 eV) and a two-grid ion optics is used for higher energies (up to 750 eV). A complementary weight loss approach is also used to measure total sputter yields. Validation experiments are presented that confirm high sensitivity and accuracy of sputter yield measurements.

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.