Explanation of threshold voltage scaling in enhancement-mode InAlN/AlN–GaN metal oxide semiconductor high electron mobility transistors on Si substrates

Self‐aligned normally‐off metal–oxide–semiconductor n++GaN/InAlN/GaN high electron mobility transistors

“…ALD is done at 100 °C through the same photoresist mask which is used for the dry etching as well as for the metal lift‐off, so that the self‐aligned concept is retained. Consequently, our approach does not introduce additional capacitance beyond the gate footprint, as it does in the two‐step alignment metal–oxide–semiconductor (MOS) gate contact processing approach , or as generally introduced by the surface passivation . In our n ++ GaN/InAlN/AlN/GaN HEMT concept we combine the advantages of the self‐aligned gate approach with a scalability of V T provided by low N d,surf .…”

Band alignment between GaN and ZrO2 formed by atomic layer deposition

“…Excellent electrical characteristics of GaN metal-insulator-semiconductor (MIS) HEMTs utilizing ZrO 2 as gate dielectrics have been reported. [1][2][3][4][5][6][7] One of the main parameters which have great impact on the properties of GaNbased MIS structures is the band alignment between gate dielectric layer and GaN layer. For example, to maintain low gate leakage and small effective oxide thickness, a large conduction band discontinuity DE C (at least 1 eV) between ZrO 2 dielectric and GaN is required.…”

Influence of post-deposition annealing on interfacial properties between GaN and ZrO2 grown by atomic layer deposition

“…Excellent electrical characteristics of GaN MISHEMTs utilizing ZrO 2 as gate dielectrics are reported recently. [10][11][12][13][14][15] Nevertheless, several material issues should be considered for further improvement of the electrical properties for GaN MISHEMTs using ZrO 2 as gate insulators. Above all, the interface between dielectric layer and underlying GaN substrate is critical, and thermal stability of the dielectric layer at the interface is one of the most challenging requirements for application of ZrO 2 as a gate dielectric.…”