The electrical properties in AlGaN/GaN heterostructures with Si- and Al-based insulators (Si3N4, SiO2, AlN, and A12O3) have been examined and analyzed. By insulators deposition, significant increase in the two-dimensional electron gas (2DEG) density (Ns) was observed with the order of NS(Al 2O3) > NS(AlN) ̃ Ns(SiO 2) > Ns(Si3N4) > No (No: Ns without insulators). As the result, the decrease in the sheet resistance (R) was observed; the smallest order of R was R(Al 2O3) > R(AlN) > R(Si3N4) > Ro ̃ R(SiO2) (Ro: R without insulator). The insulators deposition effect has thus been shown to be significant and different among insulators. The increase in Ns was analyzed in terms of the change in the potential profile, and the observed differences in N s among insulators have been interpreted. The band engineering including insulators is indispensable in understanding and designing AlGaN/GaN HFETs, since insulators are commonly used for the surface passivation as well as for the gate insulators, and the insulators deposition is to alter the essential device parameters such as the source resistance.
|Number of pages||4|
|Journal||Physica Status Solidi (C) Current Topics in Solid State Physics|
|Publication status||Published - 2007|
ASJC Scopus subject areas
- Condensed Matter Physics