Using vertical capacitance-voltage measurements for fast on-wafer characterization of epitaxial GaN-on-Si material

We propose and demonstrate an efficient approach to extract key parameters of GaN‐based 2DEG heterostructures grown on conducting Silicon substrates. The methodology enables an electrical feedback on different epitaxial design or MOCVD growth conditions in a very short‐time frame by means of vertical capacitance–voltage (C–V) measurement on simple gate‐metal top‐electrodes, which are evaporated through a shadow mask. Key parameters such as sheet charge carrier density of the 2DEG‐channel, (AlGaN) barrier thickness between 2DEG and top‐electrode and threshold voltage of 2DEG depletion can be extracted with minimum effort. All respective parameters can be logged across the entire wafer without the need for a sophisticated device process and reveal the lateral (in‐) homogeneity of the wafer material. In addition, this method can be used to mimic the gate‐module of metal–insulator–semiconductor (MIS)‐HEMTs and, therefore, to study different charge‐related properties of the dielectric‐GaN interface or the dielectric layer itself.