In this paper, we analyze the effects of temperature (from -50°C to 200°C), substrate impedance, and substrate thickness on the noise figure (NF) and quality factor (Q-factor) performances of monolithic RF inductors on silicon. A 0.45 dB (from 0.6 dB to 0.15 dB) reduction in minimum NF (NFmin) at 10 GHz, a 308% (from 11.6 to 47.3) increase in Q-factor at 10 GHz, and a 4% (from 20 GHz to 20.8 GHz) improvement in self-resonant frequency (fSR) were obtained if post-process of proton implantation had been done. In addition, a 0.36 dB reduction (from 0.6 dB to 0.24 dB) in NFminat 10 GHz, a 176% (from 11.6 to 32) increase in Q-factor at 10 GHz, and a 30% (from 20 GHz to 26 GHz) improvement in fSRwere achieved if the silicon substrate was thinned down from 750 μm to 20 μm. This means both the proton implantation and the silicon substrate thinning are effective in improving the NF and Q-factor performances of monolithic RF inductors on silicon. The present analyses are helpful for RF designers to design high-performance fully on-chip LNAs and VCOs for single-chip receiver front-end or 3.1-10.6 GHz ultra-wide-band (UWB) system applications.