Study of high Al fraction in AlGaN barrier HEMT and GaN and InGaN channel HEMT with In 0.17 Al 0.83 N barrier
- PDF / 2,185,563 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 3 Downloads / 146 Views
(0123456789().,-volV)(0123456789(). ,- volV)
TECHNICAL PAPER
Study of high Al fraction in AlGaN barrier HEMT and GaN and InGaN channel HEMT with In0.17Al0.83N barrier Krishnpriya Sinha1 • Shashank Kumar Dubey1 • Aminul Islam1 Received: 16 December 2018 / Accepted: 2 May 2019 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract This paper investigates to find a method to improve the design parameters such as drain current, transconductance, cut off frequency and most importantly minimum noise figure of the Nitride HEMTs. Firstly, to improve the performance of the Nitride HEMT, the AlGaN barrier with high Al fraction was used. Owing to its higher carrier density at higher Al fraction, AlGaN/GaN HEMT exhibited higher drain current, higher transconductance. It also results in a lower minimum noise figure. But, the increase of Al in barrier leads to a lattice mismatch of barrier layer with GaN channel layer. Thus, In0.17Al0.83N barrier layer which is lattice matched to GaN is used instead of traditionally popular AlGaN. Along with a change of material of the barrier layer, a change of material of the channel layer shows improvement in DC & RF response and most importantly in the minimum noise figure when InGaN replaces GaN. The noise performance has been further improved with the T-shaped gate by reducing the gate resistance. All the theoretical analyses have been supported and verified by the results obtained from simulation carried out using Silvaco TCAD tool.
1 Introduction High electron mobility transistor (HEMT) is a field effect transistor which has hetero materials having different band gaps to form a junction. A wide band gap material is grown on top of the narrow band material. The wide band gap material is highly doped with donor type of atoms and narrow band material is left undoped. At the junction, the band offset takes place. The excess electrons diffuse across the junction to the conduction band of narrow band gap undoped material and get accumulated there. A quantum well is formed in the undoped region and electrons get confined in it, forming a two-dimensional electron gas (2DEG). The mobility of electrons is very high in this region. These devices can be operated at high frequencies and provide low noise figure. They find their usage in low noise small signal amplifier, oscillators and mixers. With the rise in demand of RF and microwave technology in the last couple of decades, the conventional semiconductors could not meet the demand due to various limitations in their applications involving high power and & Aminul Islam [email protected] 1
high frequency. This has paved the way for wide band gap materials like GaN, GaAs, etc. The traditional HEMTs were made up of GaAs as they were the natural choice for high frequency devices. However, in the last decade, GaN is being preferred instead of GaAs as it has a wider band-gap of 3.43 eV in comparison to 1.4 eV of GaAs, higher saturation velocity (2.7 9 107 cm/s) than GaAs (2.0 9 107 cm/s) and most importantly, higher breakdow
Data Loading...
