Two-dimensional quantitative mapping of arsenic in nanometer-scale silicon devices using STEM EELS-EDX spectroscopy.

Field emission gun (FEG) nanoprobe scanning electron transmission microscopy (STEM) techniques coupled with energy dispersive X-ray (EDX) and electron energy loss spectroscopy (EELS) are evaluated for the detection of the n-type dopant arsenic, in silicon semiconductor devices with nanometer-scale. Optimization of the experimental procedure, data extraction and the signal-to-noise ratio versus electron dose, show that arsenic detection below 0.1% should be possible. STEM EDX and EELS spectrum profiles have been quantified and compared with secondary ion mass spectrometry (SIMS) analyses which show a good agreement. In addition, the arsenic doping level found inside large and small epitaxial devices have been compared using STEM EDX-EELS profiling. The average doping level is found to be similar but variable interface segregation has been observed. Finally, STEM EDX arsenic mapping acquired in a BiCMOS transistor cross-section shows strong heterogeneities and segregation in the epitaxially grown emitter part.

Gain measurements of Fabry-Perot InP/InGaAsP lasers using an ultrahigh-resolution spectrometer.

Measurements of the optical gain in a semiconductor laser using a 20 MHz resolution optical spectrum analyzer are presented for what is believed to be the first time. The high resolution allows for accurate gain measurements close to the lasing threshold. This is demonstrated by gain measurements on a bulk InGaAsP 1.5 microm Fabry-Perot laser. Combined with direct measurement of transparency carrier density values, parameters were determined for characterizing the gain at a range of wavelengths and temperatures. The necessity of the use of a logarithmic gain model is shown.