Electron spectroscopy employing controlled surface charging

A method of examining a sample, comprising:

• performing a first spectroscopic analysis of a surface portion of the sample when the sample surface portion is in a first electrical charge state;
• placing the sample surface portion in a second electrical charge state that is different from the first electrical charge state and performing a second spectroscopic analysis of the surface portion of the sample when the sample surface portion is in the second electrical charge state;
• and
• comparing the first spectroscopic analysis result with the second spectroscopic analysis result to obtain at least one of structural and electrical information about the sample,
• wherein each spectroscopic analysis result contains data identifying a characteristic of the spectral response for each of at least two elements contained in the sample, and said step of comparing includes
• determining, for each of the at least two elements contained in the sample, a difference between the first spectroscopic analysis result and the second spectroscopic analysis result and
• correlating the differences determined in the determining step for the at least two elements to provide a quantitative value of a characteristic of the sample, and the first and second electrical charge states are given values that enable information to be obtained about sample structural features having dimensions down to 1 nm.

Apparatus for examining a sample, comprising:

• a spectroscopic analysis instrument including a component that places a surface portion of the sample in different electrical charge states, for performing a first spectroscopic analysis of a surface portion of the sample when the sample surface portion is in a first electrical charge state and performing a second spectroscopic analysis of the surface portion of the sample when the sample surface portion is in a second electrical charge state different from the first electrical charge state;
• and
• an arithmetic unit coupled to said instrument to compare the first spectroscopic analysis result with the second spectroscopic analysis result to obtain at least one of structural and electrical information about the sample,
• wherein each spectroscopic analysis result contains data identifying a characteristic of the spectral response for each of at least two elements contained in the sample, and the comparison performed by the arithmetic unit includes the steps of
• determining, for each of the at least two elements contained in the sample, a difference between the first spectroscopic analysis result and the second spectroscopic analysis result and
• correlating the differences determined in the determining step for the at least two elements to provide a quantitative value of a characteristic of the sample, and
• the first and second electrical charge states are given values that enable information to be obtained about sample structural features having dimensions down to 1 nm.