AlGaN/GaN MIS-HEMT gate structure improvement using Al2O3 deposited by PEALD

Richard Meunier (1) , Alphonse Torres (1) , Matthew Charles (1) , Erwan Morvan (1) , Marc Plissonnier (1) , Frédéric Morancho (2)

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
2 LAAS-ISGE - Équipe Intégration de Systèmes de Gestion de l'Énergie

The enhancement of electric properties of MIS structures on an AlGaN/GaN heterostructure using Al2O3 a gate dielectric are investigated using C(V) and Id(Vg) measurements. The Al2O3 layer was deposited using two types of atomic layer deposition (ALD) techniques: thermal ALD and plasma enhanced ALD. Using PEALD over thermal ALD led to an increase of the threshold voltage Vth of 4V, and the suppression of non-uniform C(V) behavior by reducing traps at the Al2O3/AlGaN interface. Gate leakage current was also reduced by 6 decades and an Ion/Ioff ratio of 109 was achieved, with a subthreshold slope of 81mV/decades. Further improvements were achieved by gate recess etching before the high-k deposition through BCl3 reactive ion etching (RIE). We were able to further increase Vth by 4V while reducing gate leakage current, achieving a 1010 Ion/Ioff ratio, without degrading the subthreshold slope and the abruptness of the transition.

Mots clés: MIS structures; AlGaN/GaN heterostructures; Al2O3; gate dielectric; thermal ALD; plasma enhanced ALD; C(V)

Domaines: Electronique

Richard Meunier, Alphonse Torres, Matthew Charles, Erwan Morvan, Marc Plissonnier, et al.. AlGaN/GaN MIS-HEMT gate structure improvement using Al2O3 deposited by PEALD. 224th ECS Meeting, Oct 2013, San Francisco, United States. pp.269-277, ⟨10.1149/05804.0269ecst⟩. ⟨hal-01054216⟩