Structural and electrical characteristics of atomic layer deposited high κ HfO2 on GaN

Abstract

High HfO 2 was deposited on n-type GaN ͑0001͒ using atomic layer deposition with Hf͑NCH 3 C 2 H 5 ͒ 4 and H 2 O as the precursors. Excellent electrical properties of TiN / HfO 2 / GaN metal-oxide-semiconductor diode with the oxide thickness of 8.8 nm were obtained, in terms of low electrical leakage current density ͑ϳ10 −6 A/cm 2 at V FB +1 V͒, well behaved capacitance-voltage ͑C-V͒ curves having a low interfacial density of states of 2 ϫ 10 11 cm −2 eV −1 at the midgap, and a high dielectric constant of 16.5. C-V curves with clear accumulation and depletion behaviors were shown, along with negligible frequency dispersion and hysteresis with sweeping biasing voltages. The structural properties studied by high-resolution transmission electron microscopy and x-ray reflectivity show an atomically smooth oxide/GaN interface, with an interfacial layer of GaON ϳ1.8 nm thick, as probed using x-ray photoelectron spectroscopy.

High κ dielectric single-crystal monoclinic Gd2O3 on GaN with excellent thermal, structural, and electrical properties

“…HfO 2 ) [3][4][5][6] and single-crystal (Gd 2 O 3 , Sc 2 O 3 ) [7,8] high k dielectrics on GaN with low interfacial densities of states (D it ) and low electrical leakage currents, essential in fabricating inversion-channel devices, have received research interest recently. Annealing at very high temperature of at least 1100 1C is needed to activate source/drain implanted ions for ohmic contacts in fabricating inversion-channel GaN MOS field-effect-transistors (MOSFET's) [9,10].…”

Investigations of GaN metal-oxide-semiconductor capacitors with sputtered HfO2 gate dielectrics

“…Many effective techniques are available for depositing insulators on GaN. They include plasma-enhanced chemical vapor deposition (PE-CVD), ebeam evaporation, low-pressure CVD, photo-CVD, sputtering and atomic layer deposition [10][11][12]14,15]. Among these techniques, sputtering offers the advantages of simplicity process, low cost and high throughput.…”

“…Among these techniques, sputtering offers the advantages of simplicity process, low cost and high throughput. Besides, various chemical solutions such as H 3 PO 4 , H 2 SO 4 + H 2 O 2 , H 3 PO 4 , HF, and HCl have been applied to clean the GaN surface prior to the oxide deposition [9][10][11][12][13]. The performance of the MOS capacitors depends sensitively on the surface chemistry of as-grown GaN.…”

Impact of Al2O3 incorporation on device performance of HfO2 gate dielectric AlGaN/GaN MIS‐HFETs

“…To solve this problem, a variety of insulators [1][2][3][4] 2 have been explored as the gate dielectric (and also as the surface passivation layer) in metal-insulator-semiconductor (MIS) HFETs. Among these insulators, HfO 2 , with a high dielectric constant (high-k of ~20-25) and a relatively large band gap (~5.6 eV) has attracted interest to be used to passivate GaN-based devices [3,4]. However, its relatively low poly-crystallization temperature of ~500 o C, which may pose thermal stability concerns for the devices, hinders the realization of its full potential.…”