Characterization of AlGaN Thickness and Sheet Carrier Concentration of AlGaN/GaN Based HEMT Using Electrical Measurement

We present a simple non-destructive technique to characterize the AlGaN barrier layer thickness and sheet carrier concentration for AlGaN/GaN heterostructure. Characterization of AlGaN thickness and sheet carrier concentration has been carried out for AlGaN/GaN HEMT structure using the capacitance–voltage characterization of FATHEMT (dimension Lg = 20 µm, Wg = 150 µm). The estimated values for AlGaN thickness and the sheet carrier concentration (ns) were ~23.2 nm and ~1e13/cm2 respectively for MBE grown structure. The estimated values of AlGaN thickness are fairly matching well with measured data of HRXRD within variation of ±5 % and the estimated sheet carrier concentration values are also of the same order as evaluated using Hall Measurement.