Introducing the AlGaN/GaN/InAlGaN/GaN Dh-Hemt Structure and it is Functional Analysis
Abstract
In this article we present a new Al0.3Ga0.7N/GaN/InxAlyGa1-x-yN/GaN double Heterojunction HEMT (DH-HEMT) structure. In this structure a thin layer of InxAlyGa1-x-yN was inserted within the GaN channel. Compared with the baseline AlGaN/GaN HEMTs, The InAlGaN layer provides a unique piezoelectric polarization field which results in a higher potential barrier at the backside of the two-dimensional electron gas channel, effectively improving the carrier confinement and then reducing the buffer leakage. Also the DH-HEMT shows higher carriers density and conductivity. This device is obtained, replacing the InAlGaN for InGaN in Al0.3Ga0.7N/GaN/In0.1Ga0.9N/GaN DH-HEMT structure, for increasing the breakdown voltage. Because in this structure the InGaN alloy, which has the role of minor channel in the structure, has a small critical electric field (∼1.75 Mv/cm) rather than the (2 Mv/cm) GaN alloy (the channel in the conventional AlGaN/GaN HEMTs). So in order to increase the breakdown voltage in this structure it has been tried to find a substitute for the InGaN, so that it can keep the proper specifications of InGaN and have a bigger critical electric field (Ecrit) rather than GaN and InGaN. Lately the InAlGaN alloy, possessing the goal specification, has been noticeable. In order to achieve the best specifications, different amounts of In, Al are considered in the InAlGaN structure so that, the Ecrit have a bigger magnitude 2 Mv/cm (Ecrit in GaN alloy) and the polarization charge shows a proper magnitude as well. In AlGaN/GaN/In0.15Al0.2GaN/GaN DH-HEMT structure rather than the AlGaN/GaN/InGaN/GaN DH-HEMT has small decrease in carrier density and conductivity, but the breakdown voltage has increased, Hence there is no remarkable breakdown voltage rather than the conventional AlGaN/GaN HEMTs, also at the end we have improved structure of AlGaN/GaN/In0.15Al0.08GaN/GaN DH-HEMT that carrier density and conductivity and breakdown voltage was improvement rather than InGaN DH-HEMT.
- Publication:
-
International Congress on Advances in Applied Physics and Materials Science
- Pub Date:
- December 2011
- DOI:
- 10.1063/1.3663121
- Bibcode:
- 2011AIPC.1400..240S
- Keywords:
-
- high electron mobility transistors;
- electron gas;
- voltage measurement;
- polarization;
- 85.30.Tv;
- 73.20.At;
- 84.37.+q;
- 76.70.Fz;
- Field effect devices;
- Surface states band structure electron density of states;
- Measurements in electric variables;
- Double nuclear magnetic resonance dynamical nuclear polarization