The Veeco/CNT Fiji® has been at the forefront of recent advances in III-V devices. This includes deposition of III-V materials like AlN, InN and GaN via atomic layer epitaxy (ALE), epitaxial growth of device quality ternary compounds like AlxGa1-xN and InlxAl1-xN, deposition of buffer layers to enable hetero-epitaxy and growth of gate dielectrics and passivation layers
Epitaxial growth of device quality AlN [2], InN [1] and GaN [3] has recently been demonstrated in an Veeco/CNT Fiji®. In Fig.1 below, HRTEM and IFFT confirms crystalline InN aligned with a-sapphire. Fig.2 shows the high quality of AlN grown on GaN – the FWHM of the rocking curve is 670 arc sec for a 37nm film – this is comparable to 1.6μm grown by MBE (420 arc sec) .
High Electron Mobility Transistor is based on formation of a high mobility 2D electron gas at interface between lattice-matched semiconductors. Table-1 shows low carrier concentration and high mobility in an all ALD HEMT device (ALE GaN/ALE AlGaN/ALD Al2O3) indicating the presence of the 2D electron gas. Additionally, HEMT device performance improvement has been shown [5] due to surface passivation by ALE-AlN. Hybrid graphene/III-N heterostructures have been grown [6] enabled by the low temperature of ALD which preserves the surface functionalization of graphene.
| Sample | μ (cm2/V-s) | Ns (cm-2) |
|---|---|---|
| AlGaN / GaN | 1042 | 1.6 x 1012 |
| Al2O3 / Al0.27Ga0.73N / GaN | 871 | 6.0 x 1011 |
Figure 1: InN on sapphire [1]
Figure 2: Peaks from AlN/GaN/a-sapphire [2]