High-Q inductors on locally semi-insulated Si substrate by helium-3 bombardment for RF CMOS integrated circuits

Ning Li, Kenichi Okada, Takeshi Inoue, Takuichi Hirano, Qinghong Bu, Aravind Tharayil Narayanan, Teerachot Siriburanon, Hitoshi Sakane, Akira Matsuzawa
2014 2014 Symposium on VLSI Technology (VLSI-Technology): Digest of Technical Papers  
A novel helium-3 ion bombardment technique is proposed for creating locally semi-insulating substrate areas. A helium-3 dose of only 1.5x10 13 cm -2 increases a Si substrate resistivity from 6Ω-cm to 1.5kΩ-cm, which improves the quality factor of a 2-nH inductor with a 140µm-diameter by 38% (Q=16.3). An aluminum mask is used for covering active areas, and at most 15-µm distance from the mask edge is required to avoid the p-n junction leakage. The proposed technique is applied to an 8-GHz
more » ... to an 8-GHz oscillator, and an 8.5-dB improvement in the measured phase noise has been achieved.
doi:10.1109/vlsit.2014.6894430 fatcat:6xkoklvsjzfa7mqs3p2sosatty