| Autor: |
Hideki Ohmori, Y. Satoh, Osamu Ikata, Masanori Ueda, Tokihiro Nishihara, Osamu Kawachi, Hidema Uchishiba, Ken-ya Hashimoto |
| Rok vydání: |
2002 |
| Předmět: |
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| Zdroj: |
1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium. |
| DOI: |
10.1109/ultsym.1995.495552 |
| Popis: |
The paper presents ion implantation technology to improve the shape factor of a ladder-type SAW RF filters for mobile communication systems. The improvement of the shape factor was confirmed experimentally. However we found that the SAW phase velocity is decreased by ion implantation. To stabilize and recover the SAW phase velocity, several annealing conditions were investigated. At the annealing condition of over 450/spl deg/C/spl times/1 hour, SAW phase velocity was recovered to almost the same as the initial velocity. In the past, the shape factor values of ladder-type SAW filters using a LiTaO/sub 3/ substrate have been almost 1.7. The ion implantation technology has been applied to a PDC (personal digital cellular) -1.5 GHz SAW band pass filter using a LiTaO/sub 3/ substrate. We have obtained the shape factor value of 1.4 under the following conditions; ion: double charge Ar/sup ++/, dose: 5/spl times/10/sup 13//cm/sup 2/, acceleration voltage: 180 keV. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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