Patent ID: 7999540

Claim:
A semiconductor processing apparatus, comprising: a direct current (DC) coupled marginal oscillator to generate a time-dependent drive current, wherein the marginal oscillator includes: a first transistor and a second transistor comprising a long-tailed pair, and a third transistor, the third transistor being coupled with the first transistor to provide DC feedback through a base of the first transistor; and a coil that generates a time-dependent magnetic field that couples with a portion of a conductive region on a wafer; wherein a first end of the coil is coupled with a collector of the third transistor and the base of the first transistor by first current carrying paths that do not pass through any of the coil, the first transistor, the second transistor, and the third transistor and do not pass through a voltage supply line and ground; and wherein a second end of the coil and a base of the second transistor are coupled with ground by second current carrying paths that do not pass through any of the first current carrying paths, the coil, the first transistor, the second transistor and the third transistor and do not pass through a voltage supply line.