Terahertz imaging of silicon wafers

Abstract

Silicon samples with and without implanted layers have been imaged with a standard time-domain terahertz ͑THz͒ imaging system. The carrier concentration and mobility of the substrate have been extracted from the frequency dependence of the THz transmittance using a simple model based on the Drude approximation. The carrier concentration of implanted layers could be determined simply from the relative amplitude of the main THz pluse with a spatial resolution of Ϸ1 mm. Both substrates and thin layers of a semiconductor were characterized with the same THz system.

Hole diffusion profile in a p-p+ silicon homojunction determined by terahertz and midinfrared spectroscopic ellipsometry

“…Measurements of plasma frequency properties in a transmission configuration at terahertz frequencies have been used for the determination of free-charge-carrier properties in single crystals. [1][2][3][4][5][6][7] Characterization of free-charge-carrier properties in low-doped homo-and heterostructures remains a challenge. Specifically, the transmission configuration is inapplicable for overlayers with low charge densities deposited on highly doped substrates, since strong plasma absorption occurs for terahertz wavelengths within the substrate.…”

Terahertz wave imaging: horizons and hurdles

“…The first system [2] demonstrated an acquisition rate of 12 pixels/s. Recently, a 50 pixels/s rate has been demonstrated [34] but significant advances are required to allow real-time imaging. Two-dimensional electro-optic sampling has been used together with a CCD camera to provide a dramatic increase in imaging speed [3] and rates as high as 5000 pixels/s are feasible.…”

ZnTe single crystal growth by the liquid encapsulated pulling method

“…Rectangular facet growth was observed in 〈100〉 growth and hexagonal facet growth was observed in 〈110〉 growth. The etch pit density of the grown crystal was lower than 10000 cm -2 and the strain in the crystal was lower than that of modified liquid encapsulated Kyropoulos method.1 Introduction ZnTe is a promising material for pure-green light emitting diodes (LEDs), green laser diodes (LDs) [1, 2] and electro-optic (EO) devices [3][4][5]. In order to develop these ZnTe based applications, large diameter single crystal substrates are necessary.…”