[10p-Z04-1~17] 13.7 Compound and power electron devices and process technology

▲ [10p-Z04-6] Side gate modulation of AlGaN/GaN HEMTs on GaN with C and Fe doped buffers

〇(PC)Maria Villamin¹, Takaaki Kondo¹, Naotaka Iwata¹ (1.Toyota Technological Institute)

Keywords:GaN, HEMT, buffer layer

Side gate modulation of AlGaN/GaN HEMTs on GaN substrate with C and Fe doped buffers is investigated. Evidence of larger memory effect in HEMT on C-doped GaN buffer (C-doped GaN), compared to on Fe-doped GaN buffer (Fe-doped GaN), is demonstrated as shown in the hysteresis feature of drain current (I_D) using dual-sweep side gate (SG) measurements. C-doped GaN and Fe-doped GaN were used in this study with SG contact located at the device border separated with a distance of 6 µm, and etched 100 nm below the surface. SG modulation was done by sweeping SG voltage (V_SG) from -28 V to 8 V, and 8 V to -28 V while monitoring drain current (I_D). The drain-to-source voltage was kept at 6 V, while the gate voltage was kept at 0 V (on state). Results on C-doped GaN show an apparent hysteresis feature in I_D – V_SG but it is not evident in Fe-doped GaN. This implies that memory effect exists in C-doped GaN. Moreover, our result shows decrease in I_D at negative V_SG, which is inferred to be due to the field modulation caused by the side gate. Based on our experimental data, it can be concluded that C-doped GaN has a I_D hysteresis feature and is less stable to SG modulation as compared to Fe-doped GaN.