Deep UV-assisted capacitance–voltage characterization of post-deposition annealed Al2O3/ β -Ga2O3 (001) MOSCAPs

Abstract

In this Letter, the interface state density (Dit) and bulk trap density (nbulk) in post-deposition annealed Al2O3/β-Ga2O3 (001) metal–oxide–semiconductor capacitors (MOSCAPs) are extracted using the deep UV-assisted capacitance–voltage method and an improved physical analytical model. The effects of atomic layer deposition (ALD) temperature and post-deposition annealing (PDA) conditions are also studied. Increasing the deposition temperature and PDA at 500 °C in O2 seems to be an effective way to improve the forward breakdown voltage (BV) and suppress capacitance–voltage hysteresis in Al2O3/β-Ga2O3 (001) MOSCAPs. These results are useful for future high performance Ga2O3-based metal-oxide-semiconductor field effect transistors (MOSFETs) and Fin-FETs.

Low-energy Ga2O3 polymorphs with low electron effective masses

“…Various theoretical studies address the physical properties of the b-phase and experimental studies the preparation of non-b-phases. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] In the present work, we predict three Ga 2 O 3 polymorphs, which we call P2 1 /c Ga 2 O 3 , Pnma-I Ga 2 O 3 , and Pnma-II Ga 2 O 3 according to their space groups. The formation energy of Pnma-II Ga 2 O 3 is found to be 3 meV per atom lower than that of a-Ga 2 O 3 .…”

Vertical GaN and Vertical Ga2O3Power Transistors: Status and Challenges

“…So far, aluminum oxide (Al 2 O 3 ) is explored extensively in Ga 2 O 3 power devices due to its high-k properties and reasonable critical electric field. [92][93][94] However, to obtain the best dielectric for Ga 2 O 3 , extensive studies need to be performed. The ideal gate-dielectric needs to have a large conduction band offset, low interface and bulk traps, high-k, large critical field strength, low gate leakage, and electron and hole injection under stress.…”

In Situ Dielectric Al2O3/β‐Ga2O3 Interfaces Grown Using Metal–Organic Chemical Vapor Deposition

“…Using Equation (3), the value of ΔE C is calculated to be 1.7 eV which matches well with the previous reports on the ALD Al 2 O 3 /β-Ga 2 O 3 heterostructure. Now, to find the density of all the initially filled slow near interface states and the trap distribution as a function of energy dependence near the β-Ga 2 O 3 band edge, we use UV-assisted CV technique developed by Swenson et al [31] and later modified by Liu et al [32] This technique was also used by Jian et al [21] for ALD Al 2 O 3 /(001) β-Ga 2 O 3 MOSCAPs and briefly summarized here. The MOSCAPs were first taken from D to A and kept at accumulation for 10 min to fill all the interface states.…”

“…[18][19][20] Jian et al studied the effects of PDA on the interface trap density of the ALD deposited Al 2 O 3 on (001) β-Ga 2 O 3 . [21] In all these reported works the deposition of Al 2 O 3 is primarily performed using ex situ technique such as atomic layer deposition (ALD), where after its growth, the gallium oxide substrate or epilayer is taken to a different reactor for dielectric deposition. During such a transfer step, it is hard to completely remove any interface contamination.…”