Passivation-layer thickness and field-plate optimization to obtain high breakdown voltage in AlGaN/GaN HEMTs with short gate-to-drain distance. (June 2021)

• Record Type: Journal Article
• Authors: Iwamoto, Takuma; Akiyama, Seiya; Horio, Kazushige
• Is Part Of: Microelectronics and reliability. Volume 121(2021)
• Publication Date: 2021-06
• Subjects: Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2021.114153
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: A two-dimensional analysis of the off-state breakdown characteristics in field-plate AlGaN/GaN HEMTs is performed. The gate-to-drain distance is 1.5 μm, and the parameters are the SiN passivation-layer thickness d and the field-plate length L FP . For a moderate d of 0.1 μm, the breakdown voltage V br increases with L FP, and takes an maximum value (~400 V) around L FP = 0.3 μm, and decreases when L FP becomes even longer. This decrease is attributed to the fact that the drain voltage is almost applied along the region between the field plate and the drain. For thin d ≤ 0.03 μm, V br becomes relatively low (≤150 V) when L FP becomes long (≥ 0.6 μm). This is attributed to the fact that when d is very thin, the field plate acts like a gate electrode. When d is relatively thick (≥0.3 μm), V br decreases at L FP = 0.3 μm as compared to the case of d = 0.1 μm, and it decreases to 250 V at d = 0.5 μm. This is because the field-plate effects become weak for thick d . The optimum thickness of the SiN passivation layer is approximately 0.1–0.2 μm and V br peaks at approximately 400 V when L FP = 0.3 μm. The novelty of this paper is to show the dependence of V br on the passivation-layer thickness d and the field-plate length L FP when the gate-drain distance is short. Highlights: 2D analysis of field-plate AlGaN/GaN HEMTs with short gate-to-drain distance is performed. Dependence of breakdown voltage on passivation-layer thickness d and field-plate length LFP is analyzed. Optimum values of d and LFP are obtained to achieve high breakdown voltage.