Dual-Layer Semi-Insulating GaN Substrates Doped with Fe, C, or Mn

The compatibility of impurity doping and the suppression of residual stress are crucial for fabricating a semi-insulating GaN (SI-GaN) substrate. Herein, a new method to fabricate several SI-GaN substrates, including a dual-layer SI-GaN substrate comprising upper approximate to 100 mu m-thick GaN doped with Fe, C, or Mn and a lower approximate to 300 mu m-thick unintentionally doped GaN, using hydride vapor-phase epitaxy is proposed. As a result, substrates doped with Fe, C, or Mn are successfully produced without cracks and pits. Resistivities around a doping concentration of approximate to 10(18) cm(-3) are up to 6.6 x 10(8), >10(12), and >10(12) omega cm at room temperature, respectively. The residual stress of the dual-layer SI-GaN film is also evaluated.