Natasja Duhayon

Scanning spreading resistance microscopy and spectroscopy for routine and quantitative two-dimensional carrier profiling

As emphasized in the International Technological Roadmap for Semiconductors (ITRS), two-dimensional carrier profiling is one of the key elements in support of technology development. Scanning spreading resistance microscopy (SSRM) has been demonstrated to have attractive concentration sensitivity, an easy quantification, and is applicable to complementary metal–oxide–semiconductor Si and InP structures. Its commercial implementation and availability together with an ample supply of appropriate (diamond based) tips has enabled its more widespread use during recent years. In this article we propose a number of measurement procedures and software tools for its more reliable and fast routine application. First we present a program for the automatic generation of calibration curves and the fast quantification of one-dimensional and two-dimensional resistivity (and carrier) profiles. In view of the large tip consumption, a fast evaluation and calibration of newly mounted conductive tips is a major issue. Furthe...

Detailed study of scanning capacitance microscopy on cross-sectional and beveled junctions

In this work we have done a systematic study with scanning capacitance microscopy (SCM) on cross-sectional and beveled structures. A study was made on the practical problem of contrast reversal as well as on the effect of carrier spilling related to bevel angle, steepness and substrate concentration of the doping profile. A comparison has been made with the results achieved with spreading resistance profiling and also with theoretical predictions. Finally, the junction displacement for cross-sectional and beveled junctions is studied as a function of the applied bias. It is shown that the junction displacement is much smaller on the beveled surface after demagnification. Furthermore, the large extension of the profile along the beveled surface allows us to study the bias induced variation of the SCM signal within the depletion layer in great detail.

Carrier spilling revisited: On-bevel junction behavior of different electrical depth profiling techniques

It is well known that the electrical junction depth position measured along a beveled surface, as is routinely done in the spreading resistance probe (SRP) technique, is shallower than the corresponding metallurgical junction as seen by secondary ion mass spectrometry. The amount of on bevel junction shift (i.e., the difference in electrical on bevel versus metallurgical junction depth) in SRP has previously been attributed to a combination of material removal during the beveling (i.e., one-dimensional zero-field Poisson model) and pressure enhanced carrier spilling (enhanced permittivity). Recently the interest in the application of two-dimensional electrical characterization techniques such as scanning capacitance microscopy, with virtually zero pressure, and scanning spreading resistance microscopy, with a much smaller contact, on beveled surfaces has emerged in order to meet the needed resolutions. The data from these techniques, however, indicate that our present understanding of the carrier-spilling...

Peel-off probe: a cost-effective probe for electrical atomic force microscopy

Full metal probes have proven their suitability for electrical atomic force microscopy (AFM) in the last few years. Such probes could be fabricated cheaper if one reduces the number of steps and processing time. Therefore we have developed a procedure which allows to manufacture full metal probes with only two lithography steps. The etching of thin membranes is dropped which reduces the processing time by 25% compared to our previous procedure. It requires only topside processing. The probes can be peeled off from the wafer due to a special metallization procedure. This paper discusses the process scheme and presents measurements on semiconductor devices.

Bias-induced junction displacements in scanning spreading resistance microscopy and scanning capacitance microscopy

Scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) are both valuable tools for analyzing the two-dimensional carrier distribution in semiconductor devices. Both tools rely on the application of a bias between tip and sample to probe the relevant property (capacitance or resistance). With respect to SCM, experimental and theoretical evidence has been presented by several authors that the bias leads to a displacement of the mobile carriers and thus creates an ambiguity in the exact junction location among other carriers, leading to the concept of scanning capacitance spectroscopy. For SSRM, which originally employed a very small bias (50–100 mV), no displacement could be observed. With the advent of scanning spreading resistance spectroscopy and diamond-coated tips, higher bias voltages (up to 3–500 mV) are sometimes applied and questions are raised regarding possible distortions being induced in SSRM as well. In this article, detailed studies on the bias-induced junct...