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.

对场板AlGaN / GaN HEMT中的截止态击穿特性进行了二维分析。栅极到漏极的距离为1.5μm，参数为SiN钝化层厚度d和场板长度L _FP。对于0.1μm的中等d，击穿电压V _br随L _FP增大，在L _FP  = 0.3μm附近取最大值（〜400 V），而当L _FP变得更长时，击穿电压V _br减小。该降低归因于以下事实：漏极电压几乎沿着场板和漏极之间的区域施加。对于薄D≤0.03μm，当L _FP变长（≥0.6μm）时 ，V _br变得相对较低（≤150V ）。这归因于以下事实：当d非常薄时，场板的作用就像栅电极。当d相对较厚（≥0.3μm）时， 与d  = 0.1μm的情况相比，V _br在L _FP = 0.3μm时降低，在d  = 0.5μm时降低至250V 。这是因为，对于厚d，场板效应变得微弱。在SiN钝化层的最佳厚度为约0.1-0.2微米，V _BR峰在大约400伏时L _FP  = 0.3μm。本文的新颖之处在于，当栅极-漏极距离短时，V _br取决于钝化层厚度d和场板长度L _FP。