Low TCL, High-Q Inductors in Standard CMOS

Inductors with both a high quality factor
$\textit {Q}_{\textit {L}}$
and a low temperature coefficient of inductance
$\textrm {TC}_{\textit {L}}$
are crucial for highly stable, fully integrated frequency references. We present tapered multipath inductors in a standard CMOS technology that achieve
${\textit {Q}_{\textit {L}}} > $
8 and
${\textrm {TC}_{\textit {L}}}$
= 1 ppm/°C in aluminum-based (Al) top metal and reach
${\textit {Q}_{\textit {L}}} > $
19 with a
${\textrm {TC}_{\textit {L}}}$
= 30 ppm/°C in a thick copper-based (Cu) metal layer, both at 2 GHz.