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: A method and apparatus comprises heating a wafer to a temperature sufficient to temperature stress the wafer and enable ion motion. The wafer is then initialized in a measurement region with a non-contact corona discharge of a first polarity until a first dielectric field is developed, wherein any mobile ions present in the dielectric layer or at an air/dielectric interface move to a substrate/dielectric interface. A non-contact pulsed corona discharge of a second polarity, opposite the first polarity, is then applied to the wafer until a second dielectric field is developed and an amount of corona discharge Q.sub.MEASURED necessary to change the dielectric field from the first dielectric field to the second dielectric field is measured, wherein any mobile ions present at the dielectric/substrate interface move to the air/dielectric interface. An ideal amount of corona discharge Q.sub.

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 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: A contactless sheet resistance measurement apparatus and a method for measuring the sheet resistance of a desired layer of a first conductivity type, formed upon a substrate of an opposite conductivity type, is disclosed. The apparatus comprises a junction capacitance establishing means, a point location alternating current AC photovoltage generating means for generating a laterally propagated AC photovoltage, an attenuation and phase shift monitoring means for monitoring the .laterally propagated AC photovoltage, and a sheet resistance signal generating means responsive to the-junction capacitance establishing means, the AC photovoltage generating means, and the attenuation and phase shift monitoring means for generating an output signal indicative of a sheet resistance R.sub.S of the desired layer according to a prescribed sheet resistance model.

Abstract: The dopant concentration of a semiconductor wafer is determined using a contactless technique. First, a temporary P-N junction is formed in the surface of the semiconductor wafer using corona discharge. Then, the area of the junction is measured, and the depletion region is deepened, again by corona discharge. The depletion region is collapsed using light, and as the depletion region collapses, the surface potential is measured as a function of time. The charge which drains as the depletion layer collapses is directly proportional to the change in time. Since the total charge is known from the original corona discharge used to establish the depletion layer, as are the unit area and the surface voltage, the dopant profile is directly calculatable as a function of the surface voltage and the charge per unit area.

Abstract: A contactless technique for semiconductor wafer testing comprising: depositing charges on the top surface of an insulator layer over the wafer to create an inverted surface with a depletion region and thereby a field-induced junction therebelow in the wafer, with an accumulated guard ring on the semiconductor surface therearound. The technique further includes the step of changing the depth to which the depletion region extends below the inverted semiconductor wafer surface to create a surface potential transient, and the step of measuring a parameter of the resultant surface potential transient. This technique may be utilized to make time retention and epi doping concentration measurements. It is especially advantageous for reducing the effects of surface leakage on these measurements. In a preferred embodiment, corona discharges are used to effect the charge deposition configuration. Either corona discharge or photon injection are used to change the depletion region depth.

Abstract: A novel solid state device which exhibits two-terminal negative resistance characteristics. The negative resistance characteristic may be readily shaped by external bias control, providing a wide range of oscillatory or bistable properties. The negative resistance characteristic is obtained by a novel means of device operation exploiting an electron hole pair multiplication effect which is enhanced by high substrate doping in conjunction with appropriate biasing of the junctions within the device.The device exhibits a bias voltage controlled small signal negative resistance region, i.e., the device has a unique feature, a negative slope over an adjustable portion of its V-I characteristic. Bistable action is obtained with a single device. In the first stable state ("off") of the device, power dissipation is zero. In the second stable state ("on") of the device, power dissipation is adjustable to less than one micro-watt.

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 predominent 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.