Study of the packaging effect on blocking voltage of power devices during durability test
We investigated why the blocking voltages of a power device are lowered during a durability test through a device simulation called Technology Computer Aided Design (TCAD) and measurements using the optical beam induced current (OBIC) method. We found that the spread of the depletion layer caused by the bonding wire is what decreased the blocking voltage.
Simulation studies for avalanche induced short-circuit current crowding of MOSFET-Mode IGBT
In this paper, new theory of device failure for MOSFET-Mode IGBTs is presented, for the first time, based on large scale 3D & 2D TCAD simulations. It was found that current filaments appear when the impact ionization in the anode side exceeds a critical avalanche generation rate. The current filamentation occurs because there exist two solutions: state of current filaments and state of uniform current flow beyond the critical avalanche generation rate. Below the critical avalanche rate, there is no state of current filaments, and the device is safe. The calculated results successfully explain the previous experimental results of device failure.
A small sized lateral trench electrode IGBT for improving latch-up and breakdown characteristics
Abstract A new small sized lateral trench electrode insulated gate bipolar transistor (LTEIGBT) was proposed to improve the characteristics of conventional lateral IGBT (LIGBT) and lateral trench gate IGBT (LTIGBT). The entire electrode of LTEIGBT was replace with trench-type electrode. The LTEIGBT was designed so that the width of device is no more than 19 μm. The latch-up current densities of LIGBT, LTIGBT and LTEIGBT were 120, 540, and 1230 A/cm 2 , respectively. The enhanced latch-up capability of the LTEIGBT was obtained through holes in the current directly reaching the cathode via the p+ cathode layer underneath n+ cathode layer. The forward blocking voltage of the LTEIGBT was 130 V. Conventional LIGBT and LTIGBT of the same size were no more than 60 and 100 V, respectively. Because the proposed device was constructed of trench-type electrodes, the electric field moved toward trench-oxide layer, and punch through breakdown of LTEIGBT is occurred, lately.