Figure 2
Initial and stressed I–V characteristics under Vds of 0.1 V depending on the constant bias stresses. The constant bias stress was applied at 60 °C for 1.5 h; (a) Vg = 20 V, Vds = 0.1 V; (b) Vgs = 20 V, Vds = 40 V; and (c) Vgs = 40 V, Vds = 20 V. The black solid line indicates the initial I–V characteristics. The blue and red dashed lines are the I–V sweep signals after the stress. To clarify the current drop at the threshold voltage region by hump depending on each stress, the I–V characteristics were compared through the initial I–V shifted to the stressed I–V. (d–f) Clearly show the current drop and hump behavior in (a–c), respectively. The gap between the initial shifted and stressed I–V is marked with the blue and red colors.
