R. Fachberger, T. Holzheu, E. Riha, E. Born, P. Pongratz, H. Cerva
{"title":"Langasite和langatate非均匀材料的性质与SAW器件的性能相关","authors":"R. Fachberger, T. Holzheu, E. Riha, E. Born, P. Pongratz, H. Cerva","doi":"10.1109/FREQ.2001.956194","DOIUrl":null,"url":null,"abstract":"Material properties of Langasite (LGS) and its homologous compounds, e.g., Langatate (LGT) have been investigated employing lattice constants measurements revealing that the micro structured growth striations affect the a and c-parameter of the unit cell. Thus deviations off the congruent melt composition of the crystal are assumed. Transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDX) exhibit amorphous inclusions having a nearly identical chemical composition as the surrounding crystal. X-ray topography (XRT) has been applied to correlate the crystal quality of 3\" LGS and LGT wafers including defects and transverse growth banding (TGB) with SAW frequency shifts. Evaluation of the RF-signal of SAW test devices showed frequency deviations of about 1000 ppm even within one wafer. The pattern of the frequency shifts is related to the orientation of the TGB. Local accumulations of defects, e.g., dislocations, however, did not cause observable interference with the SAW frequency.","PeriodicalId":369101,"journal":{"name":"Proceedings of the 2001 IEEE International Frequncy Control Symposium and PDA Exhibition (Cat. No.01CH37218)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2001-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"7","resultStr":"{\"title\":\"Langasite and langatate nonuniform material properties correlated to the performance of SAW devices\",\"authors\":\"R. Fachberger, T. Holzheu, E. Riha, E. Born, P. Pongratz, H. Cerva\",\"doi\":\"10.1109/FREQ.2001.956194\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Material properties of Langasite (LGS) and its homologous compounds, e.g., Langatate (LGT) have been investigated employing lattice constants measurements revealing that the micro structured growth striations affect the a and c-parameter of the unit cell. Thus deviations off the congruent melt composition of the crystal are assumed. Transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDX) exhibit amorphous inclusions having a nearly identical chemical composition as the surrounding crystal. X-ray topography (XRT) has been applied to correlate the crystal quality of 3\\\" LGS and LGT wafers including defects and transverse growth banding (TGB) with SAW frequency shifts. Evaluation of the RF-signal of SAW test devices showed frequency deviations of about 1000 ppm even within one wafer. The pattern of the frequency shifts is related to the orientation of the TGB. Local accumulations of defects, e.g., dislocations, however, did not cause observable interference with the SAW frequency.\",\"PeriodicalId\":369101,\"journal\":{\"name\":\"Proceedings of the 2001 IEEE International Frequncy Control Symposium and PDA Exhibition (Cat. No.01CH37218)\",\"volume\":\"67 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2001-06-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"7\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Proceedings of the 2001 IEEE International Frequncy Control Symposium and PDA Exhibition (Cat. No.01CH37218)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1109/FREQ.2001.956194\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 2001 IEEE International Frequncy Control Symposium and PDA Exhibition (Cat. No.01CH37218)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/FREQ.2001.956194","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Langasite and langatate nonuniform material properties correlated to the performance of SAW devices
Material properties of Langasite (LGS) and its homologous compounds, e.g., Langatate (LGT) have been investigated employing lattice constants measurements revealing that the micro structured growth striations affect the a and c-parameter of the unit cell. Thus deviations off the congruent melt composition of the crystal are assumed. Transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDX) exhibit amorphous inclusions having a nearly identical chemical composition as the surrounding crystal. X-ray topography (XRT) has been applied to correlate the crystal quality of 3" LGS and LGT wafers including defects and transverse growth banding (TGB) with SAW frequency shifts. Evaluation of the RF-signal of SAW test devices showed frequency deviations of about 1000 ppm even within one wafer. The pattern of the frequency shifts is related to the orientation of the TGB. Local accumulations of defects, e.g., dislocations, however, did not cause observable interference with the SAW frequency.