Effects of an Fe-doped GaN Buffer in AlGaN/GaN Power HEMTs on Si Substrate

AlGaN/GaN power high electron mobility transistors (HEMTs) with a Fe-doped GaN buffer on a Si substrate were presented for high power switching applications. In order to investigate the effects of an Fe-doped GaN buffer on device characteristics, HEMT devices with an Fe-doped GaN buffer on Si were fabricated alongside with the conventional devices utilizing an unintentionally doped (UID) GaN buffer on Si, and their device characteristics were compared. It was shown that the AlGaN/GaN HEMT with a conventional structure was not suitable for realizing a high breakdown voltage (BV) due to the unstable off-state breakdown behavior. On the other hand, the AlGaN/GaN HEMT with a Fe-doped GaN buffer on Si exhibited much more stable and higher BVs by successfully suppressing the premature failure caused by Si breakdown. As a result, a BV of 295 V and the specific on-resistance (AR_DS(ON) ) of 2.44 mOmegacm₂ was achieved