Measurement of Small Junction Capacitances
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
In the manufacture of semiconductors, capacitance measurements may be used to develop models or control a manufacturing process. There is a problem with the measurement of small or low capacitance structures where the probe and pad of ordinary means is large enough to interfere with the accuracy of the measurement. An invention proposes a circuit design integrated on the same chip so that the differential channels, which are a form of a capacitance measurement circuit, are balanced within the limits of on-chip tracking. The proposed technique is based on probing the device under test with a signal which is small in amplitude, e.g., 1 millivolt, but high in frequency, e.g., 100 MHz.