A Low-Cost Low-Noise Amplifier in Poly-Si TFT Technology

Low-temperature polycrystalline silicon (poly-Si) thin-film transistors (LTPS TFTs) are emerging as promising devices for low-cost applications owing to their low manufacturing cost. Since LTPS TFTs can be fabricated on the insulating substrates such as plastic or glass, on-chip spiral inductors achieve high quality of characteristic. In this paper, we observed that inductors using LTPS TFT technology have a 14% higher Q-factor and a 16% higher self-resonance frequency compared to corresponding CMOS-bulk technology from electromagnetic (EM) simulation. It allows compensating low trans-conductance (gm) of LTPS TFTs due to inherent grain boundaries (GBs) in the poly-Si channel. With the properly optimized dimension of LTPS TFT technology, we designed a low-noise amplifier (LNA) on glass substrate having a gain = 15.4 dB, noise figure (NF)=2.8 dB, and third-order input intercept point (IIP3) = 3.9 dBm at 2.4 GHz with a 2 V voltage supply. The results demonstrate that low-cost RF design with LTPS TFTs can achieve CMOS-like performance.