Abstract: A probe, a method of making the same, and a manner of using the same, suitable for "Metal-Oxide-Semiconductor (MOS) like" electrical characterization measurements on semiconductor substrates having overlying dielectric layers is disclosed. The probe comprises an electrically conductive probe needle, the needle having a rounded tip end of a first radius, the rounded tip end further being suitable for undergoing a plastic deformation. The needle is positioned above the dielectric layer on the semiconductor substrate and the needle tip forced down onto the smooth surface of the dielectric layer in a controlled manner for causing the needle tip to undergo a plastic deformation in which an outer portion of the rounded tip end is maintained at the first radius and an inner portion of the rounded tip end is increased to a second radius, the second radius being larger than the first.

Abstract: An apparatus for measuring charge in an oxide layer overlying a silicon substrate containing very high density product chips characterized by thick oxides and high substrate doping levels in the field regions. A specially designed extremely thin conductive probe is pressed against the oxide layer whose charge is to be measured. A bias is applied to the probe for biasing the underlying silicon surface into accumulation or inversion. An intensity modulated light beam is focussed at the point of probe contact. The resulting amplitude modulated photovoltage is detected and applied to a computer to derive the value of the oxide charge therefrom.

Abstract: A method for measuring the thickness of very thin oxide layers on a silicon substrate. A corona discharge source repetitively deposits a calibrated fixed charge density on the surface of the oxide. The resultant change in oxide surface potential for each charge deposition is measured. By choosing a starting value for an assumed oxide thickness, the approximate change in silicon bandbending per corona discharge step is determined. The cumulative changes in bandbending versus oxide surface potential yields an experimental bandbending versus bias characteristic. A theoretical bandbending versus bias characteristic is established. The experimental and theoretical characteristics are matched at the predetermined points thereof and then the assumed oxide thickness is iterated until both characteristics superimpose in the silicon accumulation region. The iterated oxide thickness that allows both characteristics to superimpose is the oxide thickness value being sought.

Abstract: An inductively coupled oscillator method for inducing eddy currents in a semiconductor PN junction wafer while irradiating said wafer with pulsed light of selected intensity. The oscillator loading due to the pulsed light modulated eddy current losses is monitored and displayed on an oscilloscope in the form of a decay time plot of voltage amplitude, the plot being a function of the pulsed light intensity and the recombination rate of light-induced electrons and holes on each side of the junctions. The leakage characteristics of the junctions which are desired to be measured are one of the factors determining said rate. Leakage characteristic is made the predominant factor by setting the intensity of the pulsed light to a value which produces a nearly straight line decay time plot on the oscilloscope display. The slope of the line then is a measure of the leakage characteristic.