In-situ nitrogen plasma passivation of Al2O3/GaN interface states

Abstract

The authors report on in-situ nitrogen plasma cleaning, consisting of alternating cycles of nitrogen plasma and trimethylaluminum prior to the dielectric deposition, as an effective method to passivate Al2O3/GaN interface states. The nitrogen plasma pretreatment reduces the frequency dispersion in capacitance–voltage and the conductance peak in conductance–voltage measurements, compared to interfaces cleaned with a hydrogen plasma pretreatment. It is shown that the decrease of the trap density (Dit) below the conduction band is correlated with the suppression of Ga-O bonding and the formation of an aluminum oxynitride interfacial layer.

Oxide Charge Engineering of Atomic Layer Deposited AlOxNy/Al2O3 Gate Dielectrics: A Path to Enhancement Mode GaN Devices

“…In a prior report, nitrogen plasma was combined with trimethylaluminum dosing as a means of surface preparation of GaN substrates prior to the start of gate dielectric deposition . In contrast, in the current experiments, nitrogen is incorporated in the bulk of the Al 2 O 3 dielectric using an inductively coupled remote plasma to dissociate N 2 gas producing activated nitrogen species after each cycle of TMA/H 2 O ALD.…”

Interface formation of Al2O3 on n‐GaN(0001): Photoelectron spectroscopy studies

“…Physical vapor deposition (PVD) is successfully used for the growth of the aluminum oxide 39–41 on other substrates, and it seems like an interesting choice for an alternative to ALD‐Al 2 O 3 . Al 2 O 3 /n‐GaN system is widely studied by many groups, 3,42–48 mostly focusing on near interface trap density and electrical properties. So far, a few reports have been published on the properties of the Al 2 O 3 /n‐GaN interface formed by ALD 12,18,49 but none by PVD.…”

Measurements of nitrogen atom density in a microwave‐excited plasma jet produced under moderate pressures

“…Nitrogen plasmas have been used in various applications such as plasma passivation of polycrystalline silicon thin-film transistors [1] and Al 2 O 3 /GaN interface states [2], damage-free surface of GaN films [3], surface modification of magnetic recording media [4], nitrogen-doping of graphene [5], nitridation of silicon oxide layers [6], surface modification of carbon nanotubes [7], a Correspondence to: Jaeho Kim. E-mail: jaeho.kim@aist.go.jp *Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan **GaN Advanced Device Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya, Aichi, Japan ***Center for Low-temperature Plasma Sciences, Nagoya University, Nagoya, Aichi, Japan ****Faculty of Science and Technology, Meijo University, Nagoya, Aichi, Japan *****Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8564, Japan and a low-temperature growth of silicon nitride films [8].…”

“…In these processes, various plasma sources excited by electrical power supplies with high frequencies in the radio frequency (RF) band of 13.56 MHz [2,5,7,8,[14][15][16]20,22,24,26,27], very high frequency (VHF) band of 60 MHz [25], and microwave band of 2.45 GHz [9][10][11][12][13]17,18,21,23] have been employed to produce active nitrogen radicals at low pressures in the range from 0.4 to 267 Pa. Those sources can produce high radical densities because of the efficient electric power coupling with plasma directly through waves in the plasma [25]. However, an advanced nitrogen plasma source capable of producing higher radical densities, reducing ion bombardment damage on substrates, and enlarging processing area while maintaining uniformity is still strongly required for industrial applications.…”