Scanning capacitance - voltage microscopy

Claim 1

A method for determining a property of a material with respect to at least two dimensions, comprising the steps of: moving a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; sensing the value of a parameter corresponding to the capacitance in a region of said material near said tip for a plurality of of said voltage levels at a plurality of locations within said scan area; providing measured data for said locations, said parameter values and said voltage levels; and relating said measured data according to a predetermined relationship to derive said material property at each of the locations, whereby data for said material property is provided with respect to at least two dimensions in the region of said scan.

Claim 2

A method for determining a property of a material with respect to at least two dimensions, comprising the steps of: moving a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; sensing the value of a parameter corresponding to the capacitance in a region of said material near said tip for a plurality of of said voltage levels at a plurality of locations within said scan area; providing measured data for said locations, said parameter values and said voltage levels; and relating said measured data according to a predetermined relationship to derive said material property at each of the locations, whereby data for said material property is provided with respect to at least two dimensions in the region of said scan.

Claim 8

A method for determining dopant density of a semiconductor material with respect to at least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; applying a variable force to said tip so as to maintain said tip at a relatively constant spacing from the surface of said material as said tip is scanned; sensing the magnitude of the variable force for a plurality of said voltage levels at a plurality of locations within said scan area; providing measured data for said locations, said force magnitude and said voltage levels; and processing said measured data such that the force magnitude data provides capacitance value data of the material in the vicinity of said tip, and the capacitance value data is processed in conjunction with the voltage value data to provide dopant density data for each of the data locations, whereby data for the dopant density is provided with respect to at least two dimensions in the region of said scan.

Claim 9

A method for determining dopant density of a semiconductor material with respect to at least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; applying a variable force to said tip so as to maintain said tip at a relatively constant spacing from the surface of said material as said tip is scanned; sensing the magnitude of the variable force for a plurality of said voltage levels at a plurality of locations within said scan area; providing measured data for said locations, said force magnitude and said voltage levels; and processing said measured data such that the force magnitude data provides capacitance value data of the material in the vicinity of said tip, and the capacitance value data is processed in conjunction with the voltage value data to provide dopant density data for each of the data locations, whereby data for the dopant density is provided with respect to at least two dimensions in the region of said scan.

Claim 14

A method for determining a property of a material with respect to a least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; illuminating the material surface in the vicinity of said tip with a light source of variable intensity; sensing the value of a parameter corresponding to the capacitance in a region of said material near said tip for one or more levels of light intensity, for a plurality of of of said voltage levels, at a plurality of locations within said scan area; providing data for said locations, said parameter values, said light intensities and said voltage levels; and relating said data according to a predetermined relationship to derive said material property at each of the data locations, whereby data for said material property is provided with respect to at least two dimensions in the region of said scan.

Claim 15

A method for determining a property of a material with respect to a least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; illuminating the material surface in the vicinity of said tip with a light source of variable intensity; sensing the value of a parameter corresponding to the capacitance in a region of said material near said tip for one or more levels of light intensity, for a plurality of of of said voltage levels, at a plurality of locations within said scan area; providing data for said locations, said parameter values, said light intensities and said voltage levels; and relating said data according to a predetermined relationship to derive said material property at each of the data locations, whereby data for said material property is provided with respect to at least two dimensions in the region of said scan.

Claim 23

A method for determining a property of a material with respect to at least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined area; applying a voltage to said tip with respect to said material; sensing respective values of a parameter corresponding to the capacitance in a region of said material near said tip for a plurality of of said voltage levels at respective ones of plurality of locations within said area; relating said respective values and voltage levels according to a predetermined relationship to derive said material property at each of said respective ones of said plurality of locations, whereby data for said material property is provided with respect to at least two dimensions within said predetermined area.

Claim 24

A method for determining a property of a material with respect to at least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined area; applying a voltage to said tip with respect to said material; sensing respective values of a parameter corresponding to the capacitance in a region of said material near said tip for a plurality of of said voltage levels at respective ones of plurality of locations within said area; relating said respective values and voltage levels according to a predetermined relationship to derive said material property at each of said respective ones of said plurality of locations, whereby data for said material property is provided with respect to at least two dimensions within said predetermined area.

Claim 25

A method for determining a property of a material with respect to at least two dimensions, comprising the steps of: moving a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; sensing the value of a parameter corresponding to the capacitance in a region of said material near said tip for a plurality of of said voltage levels at a plurality of locations within said scan area; providing measured data for said locations, said parameter values and said voltage levels; and relating said measured data according to a predetermined relationship to derive said material property at each of said locations, by providing deriving means for deriving data for said parameter values and said voltage levels for said locations, from data corresponding to said property at said locations, providing input data corresponding to the estimated property values at said locations to said deriving means, and deriving first estimated data for said parameter values and said voltage levels for said locations, comparing said estimated data with said measured data, modifying said input data based on the results of said step of comparing, to derive input data corresponding more closely to the actual property values of said material, and repeating said steps of providing input data, comparing and modifying until said estimated data and said measured data differ by no more than a preselected factor, whereby data for said material property is provided with respect to at least two dimensions in the region of said scan.

Claim 26

A method for determining a property of a material with respect to at least two dimensions, comprising the steps of: moving a fine tip in close proximity to a surface of said material within a predetermined scan area; applying a voltage to said tip with respect to said material; sensing the value of a parameter corresponding to the capacitance in a region of said material near said tip for a plurality of of said voltage levels at a plurality of locations within said scan area; providing measured data for said locations, said parameter values and said voltage levels; and relating said measured data according to a predetermined relationship to derive said material property at each of said locations, by providing deriving means for deriving data for said parameter values and said voltage levels for said locations, from data corresponding to said property at said locations, providing input data corresponding to the estimated property values at said locations to said deriving means, and deriving first estimated data for said parameter values and said voltage levels for said locations, comparing said estimated data with said measured data, modifying said input data based on the results of said step of comparing, to derive input data corresponding more closely to the actual property values of said material, and repeating said steps of providing input data, comparing and modifying until said estimated data and said measured data differ by no more than a preselected factor, whereby data for said material property is provided with respect to at least two dimensions in the region of said scan.

Claim 27

A method for determining a property of material with respect to at least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined area; applying a voltage to said tip with respect to said material; sensing respective values of a parameter corresponding to the capacitance in a region of said material near said tip for one or more of said voltage levels at respective ones of a plurality of locations within said area, by applying a first force to maintain said tip at a relatively constant distance from the surface of said material, and sensing a second force generated between said tip and said material; relating said respective values and voltage levels according to a predetermined relationship to derive said material property at each of said respective ones of said plurality of locations, by relating said second force to a capacitance of said material in the vicinity of said probe by the formulas ##EQU2## where Cox=ε ox A/T, Cair=ε air A/Z, and Cd=ε Sil A/D, where T is the thickness of the oxide layer, Z is the distance between the probe and the top surface of the oxide layer, D is the depletion depth, and ε ox , ε air and ε Sil are, respectively, the dielectric constants of the oxide layer, air and silicon, and F=1/2V 2 dC/dZ where F is said second force, V is said applied voltage where, and dC/dZ is the rate of change of the capacitance of the tip and material system, including surrounding air, whereby data for said material property is provided with respect to at least two dimensions within said predetermined area.

Claim 28

A method for determining a property of material with respect to at least two dimensions, comprising the steps of: scanning a fine tip in close proximity to a surface of said material within a predetermined area; applying a voltage to said tip with respect to said material; sensing respective values of a parameter corresponding to the capacitance in a region of said material near said tip for one or more of said voltage levels at respective ones of a plurality of locations within said area, by applying a first force to maintain said tip at a relatively constant distance from the surface of said material, and sensing a second force generated between said tip and said material; relating said respective values and voltage levels according to a predetermined relationship to derive said material property at each of said respective ones of said plurality of locations, by relating said second force to a capacitance of said material in the vicinity of said probe by the formulas ##EQU2## where Cox=ε ox A/T, Cair=ε air A/Z, and Cd=ε Sil A/D, where T is the thickness of the oxide layer, Z is the distance between the probe and the top surface of the oxide layer, D is the depletion depth, and ε ox , ε air and ε Sil are, respectively, the dielectric constants of the oxide layer, air and silicon, and F=1/2V 2 dC/dZ where F is said second force, V is said applied voltage where, and dC/dZ is the rate of change of the capacitance of the tip and material system, including surrounding air, whereby data for said material property is provided with respect to at least two dimensions within said predetermined area.