A new lateral trench-gate conductivity modulated power transistor

Abstract

In this paper, a new conductivity modulated power transistor called the Lateral Trench-Gate Bipolar Transistor (LTGBT) is presented. This structure incorporates a trench-gate in which the locations of the channel and source in conventional LIGBT have been interchanged. This channel and source arrangement results in significant improvement in latch-up current density. Experimental results indicate that the static and dynamic latch-up current densities are improved by 2.3 and 4.2 times, respectively, compared to those of the LIGBT at a n+ cathode length of 5 μm. Dependence of the latch-up current density of the LTGBT on the design of the n+ and p+ cathode regions is examined both numerically and experimentally. The maximum controllable current density is found to be increased when the space between the trench-gate and the p+ cathode is reduced. Specifically, as the space is decreased to 2 μm, no latch-up phenomenon was observed. This nonlatch-up characteristic is obtained at the expense of a slight increase (0.8 V) in threshold voltage.