Lateral Charge Transport in the Carbon-Doped Buffer in AlGaN/GaN-on-Si HEMTs

“Leaky Dielectric” Model for the Suppression of Dynamic $R_{\mathrm{ON}}$ in Carbon-Doped AlGaN/GaN HEMTs

“…With a blocking heterojunction, a 2D hole gas can form at the bottom of the layer for sufficiently high field ( Fig. 2c) [17,18]. Under static bias where there is no significant substrate leakage, it is these regions that will store the majority of the charge which leads to current collapse.…”

The Impact of Ti/Al Contacts on AlGaN/GaN HEMT Vertical Leakage and Breakdown

“…This has been confirmed by the invariance of back-gate 2DEG pinch-off voltage across contacted structures with various active areas when using the Si substrate as the back-gate [3] (not shown here). The presence of lateral conduction paths (such as a 2D hole gas which can extend up to 100 μm outside the active area [18]) would have the effect of reducing the pinch off voltage in smaller active areas, but that was not seen here.…”

Control of Buffer-Induced Current Collapse in AlGaN/GaN HEMTs Using SiNx Deposition

“…The technique is especially sensitive to changes in the resistivity of the UiD (Unintentionally Doped) channel and C:GaN [14,15]. Interpretation is discussed in more detail in [11,[16][17][18]. TLM structures with a contact gap of 35 µm were used and the substrate was swept to −600V and back to 0V at 9.2V/s while a source to drain voltage of 1V was applied.…”

“…A full description of charge trapping in the HEMT will also depend on the horizontal transport. The C:GaN layer is known to be weakly p-type, [20,21] so to understand the charge storage in this layer we must consider the vertical structure of the device [15][16][17][18]. Figure 3 (Fig.…”

“…Alternatively the leakage seen in Fig. 6 through the entire stack may be dominated by preferential widely spaced leakage paths [16] which dominate over the small changes in leakage inferred fro m substrate ramps and which extend over the entire surface of the device.…”