Electrical Properties of GaN Cap Layer for AlGaN/GaN HEMT

Metal organic chemical vapor deposition (MOCVD) was used to grow AlGaN/GaN HEMT on a sapphire substrate with a 3.0 nm GaN cap and a sample without a GaN cap. High resolution X-ray diffraction (HRXRD) was utilized to investigate the structural characteristics of the materials. The relationship between the electrical properties and two-dimensional electron gas (2DEG) I-V and Hall Effect measurement. The I-V measurement was used to investigate the resistance properties of AlGaN/GaN heterostructures. Hall Effect measurement was used to quantify electron mobility and sheet carrier concentration in both samples. The sample with a 3.0 nm GaN cap exhibited excellent electrical properties with 436.8 Ω/sq sheet resistivity and possessed a high value of sheet carrier concentration 3.46E+14 per cm 2 .