Non-contact electrical characterization of GaN, SiC and AlGaN/GaN for device applications

Abstract

Corona-Kelvin metrology has been successfully applied to achieve high-precision non-contact electrical characterization of epitaxial GaN, SiC and heteroepitaxial AlGaN/GaN without fabrication of test junction or Schottky diodes. Using the constant surface potential charge deposition method, an excellent dopant repeatability with 0.05% STDEV was demonstrated for n-type GaN with ND=2.9e17cm -3 and 0.1% STDEV For n-type SiC with ND=9.0e15cm -3 . For AlGaN/GaN the results demonstrate corona-Kelvin 2DEG profiling with excellent correlation to standard mercury probe CV (MCV) measurement. However the novel charge-based technique demonstrates a unique quantification of 2DEG sheet charge using "charge to depletion". Results for oxidized GaN demonstrate interfacial characterization including Dit spectroscopy.

Wafer-level nondestructive inspection of substrate off-angle and net donor concentration of the n−-drift layer in vertical GaN-on-GaN Schottky diodes

“…The direct measurement of the net donor concentration was performed using a noncontact C-V measurement tool (Semilab Semiconductor Physics Laboratory FAaST-210). 19) Si and C concentrations were also confirmed by secondary ion mass spectrometry (SIMS).…”

Method for noncontact measurement of 2DEG mobility and carrier density in AlGaN/GaN on semi-insulating wafers

“…This is an analogy to identification of the pinch-off point in the capacitance voltage technique that uses the slope change of the integrated capacitance versus bias voltage to indicate a depleted 2DEG. 18,19) In previous work, [5][6][7] we have demonstrated for "normally on" heterostructures a practically one to one relation between the applied charge bias and the change of 2DEG density. The emptying or filling of the triangular well takes place in response to negative or positive charge bias, respectively.…”

“…5) A version of the technique known as corona noncontact C-V 5) was employed in previous research on the characterization of AlGaN/GaN heterostructures and 2DEG in the "normally on" HEMT configuration. [6][7][8] In the present work we report further developments in the noncontact corona charge-bias metrology realized with charge-assisted sheet resistance measurements. Noncontact eddy current sheet resistance, R sh measurements are commonly used by the industry for testing of AlGaN/GaN heterostructures on semi-insulating substrates.…”

“…This is accomplished with short wavelength illumination that generates minority carriers. [5][6][7] For the charge-assisted mobility technique, the noncontact sheet resistance measurements were performed with an eddy current probe for R sh measurements in the range of 200-6000 Ω/sq. This was combined with wire corona charging for sequential -R Q sh data acquisition.…”

Review—Recent Advancement in Charge- and Photo-Assisted Non-Contact Electrical Characterization of SiC, GaN, and AlGaN/GaN HEMT

“…The C-V results identify the pinch-off voltage and they are also used to calculate the carrier concentration depth profile. 9,10 The profiles are shown in Fig. 18.…”