Study On Optical Measurements For New-style Semiconductor Material Properties

As the new generation of microelectronic device become smaller in criticaldimension during the semiconductor manufacturing, very strict requirement forimplantation process in semiconductor material is required. Only the preparation of theultra-shallow junction (USJ) wafers with low implantation energy (<5keV) can satisfythose microelectronic devices. On the other hand, for solving much problem such asheat increment and power consumption from VLSI level with small critical dimension,the new-style material of Silicon-On-Insulator (SOI) is valued for development ofsemiconductor manufacturing. Naturally, properties of these new-style materials willobviously affect the microelectronic device performance. Thus monitoring of thematerial properties is indispensable to control the performance and quality of devices.Compared to other techniques, optical measurements with non-contact, non-destructiveand fast testing contain more advantage, unfortunately, except for smaller sensitivityand accuracy. Hence, photocarrier radiometry (PCR), modulated free carrier absorption(MFCA) techniques and potoluminescemce (PL) were employed in this dissertation tomeasure the properties of semiconductor materials, and to develop the higher sensitiveand accurate techniques.Based on frequency sweeping PCR and MFCA, quasi-time PCR and MFCAmodels are presented and employed to measure the semiconductor materials. In thosemodels, sample is considered as a signal processing system. The wave-modulated inputsignal (pumping beam) was handled by photocarrier in sample, then the output signal(PCR or MFCA signals) was recorded to analyze the linear and non-linear feature of thesystems. Meanwhile, under a linear approximation, the effective lifetime of carrier wereextracted from quasi-time PCR waveforms. Then, the implantation dose, theimplantation energy and the annealing temperature dependencies of PCR amplitude,effective lifetime as well as transient PCR waveforms were simultaneously employed to analyze silicon (Si) samples with B~+, P~+, and As~+ion implantation. Furthermore, theUSJ wafers with low-energy implantation were studied by PL and PCR techniques. Theexperimental results have demonstrated the optical and electronic properties of theimplanted and annealed USJ wafers. The PL signals with optical interference wereobserved from the SOI wafers with different SOI layer thickness and buried oxide layerthickness, and the quasi-time PCR signals have shown their electronic property of lowcarrier effective lifetime.In this dissertation, a time-domain three-dimensional excess carrier model formodulated free-carrier absorption (MFCA) measurement was introduced to describe thecarrier transport properties of the homogeneous structure of Si wafers. The comparativesimulations through MFCA waveforms have been performed to investigate the responseof the electronic transport parameters and instrumental parameters to this model. Usingthe MFCA setup, we have unambiguously determined the values of three transportparameters, namely, the bulk carrier lifetime, the carrier diffusion coefficient, and thefront surface recombination velocity, separately, for N type and P type Si wafers.