Anisotropic Deep Reactive Ion Etching without Aspect Ratio Dependence Etching for silicon power devices

Aurélie Lecestre (1) , Pascal Dubreuil (1) , Sylvain Noblecourt (2) , Josiane Tasselli (2) , Éric Imbernon (1) , Frédéric Morancho (2)

1 LAAS-TEAM - Service Techniques et Équipements Appliqués à la Microélectronique
2 LAAS-ISGE - Équipe Intégration de Systèmes de Gestion de l'Énergie

We present the optimization of the critical etching step for the fabrication of silicon Deep Trench-SuperJunction (DT-SJ) Diodes in order to obtain breakdown voltages of 1200V. The influence of the technological parameters on electrical performances has been studied by simulations, showing the importance of trenches verticality and width. The aim is to fabricate an array of trenches of 6 µm-width and 110µm-depth near to junction termination trenches of 80um width. The main challenge for etching deep trenches in silicon is high anisotropy with high aspect ratio: we studied the influence of DRIE passivation time on Critical Dimension loss. ARDE effect (Aspect Ratio Dependent Etching) has been reduced by using a thermal silicon oxide mask: SiO2 thicknesses have been determined in order to obtain the same depth whatever the trench aperture.

Mots clés: etching; Deep Trench; high aspect ratio; ARDE effect

Domaines: Electronique

Aurélie Lecestre, Pascal Dubreuil, Sylvain Noblecourt, Josiane Tasselli, Éric Imbernon, et al.. Anisotropic Deep Reactive Ion Etching without Aspect Ratio Dependence Etching for silicon power devices. PESM 2014 (Plasma Etch and Strip in Microtechnology), May 2014, Grenoble, France. 2p. ⟨hal-01054251⟩