Nondestructive evaluation of carrier concentration in the channel layer of In0.5Ga0.5P/In0.2Ga0.8As/GaAs heterostructure field-effect transistors by Raman scattering

Abstract

Carrier concentration (N) in the channel layers of pseudomorphic In0.5Ga0.5P/In0.2Ga0.8As/GaAs heterostructure field-effect transistors (HFETs) is evaluated by Raman scattering measurements. The coupled mode between the InGaAs longitudinal optical phonons and electrons in the InGaAs channel shifts continuously to a low wave number with an increasing N in the InGaAs channel. Preliminary calculation indicates that N can be determined with an error of less than 0.35×1018/cm3 in the 1018/cm3 order range, which corresponds to a 100 mV HFET threshold voltage. Raman scattering measurement is nondestructive and has a high spatial resolution as small as 1 μm in diameter. Thus, this measurement is promising in HFET wafer selection.

Raman imaging of semiconductor materials: characterization of static and dynamic properties

“…Spatial distributions of impurity concentration and free carrier concentration have been studied by Raman imaging [15,25,26]. The free carrier distribution in heterostructures has also been studied by several researchers [27][28][29]. Intentionally doped semiconductor wafers often have non-uniform impurity distributions.…”

Phonons inIn0.53Ga0.47As/IRowell1, Yu2, Lockwood3 et al. 2003Phys. Rev. B7000View full textAdd to dashboardCite

“…21,27 For the case of In 1Ϫx Ga x As/InP superlattices-the main interest of this paper-there has been no systematic study of the effects of strain and confinement by infrared and Raman spectroscopy. The latter method, however, has been used to probe phonons and their interaction with carriers in single In 1Ϫx Ga x As/InP quantum wells; [36][37][38][39][40][41] folded acoustic, layer, and interface modes in In 0.53 Ga 0.47 As/InP superlattices; 42,43 and strain in InAs/InP single wells 44 and superlattices. 45 In the In 1Ϫx Ga x As/InP(100) strained-layer system, the polarized infrared reflectance technique has been shown to be superior to that of Raman spectroscopy for evaluating the optical phonons over a wide concentration range.…”