The Studying Of ESD Protection Device Based On AlGaN/GaN Heterjunction

The GaN semiconductor technology has been rapid developed in the past 20 years, because the GaN material exhibits many advantages in the fields of the high temperature, the optoelectronics, the high-power, and the microwave radio frequency. Especially, as the development of the GaN epitaxy technology, the GaN-based device is drived to be rapid developed. The AlGaN/GaN high electron mobility transistor (HEMT) has wide application in the fields of the the high-power and the microwave radio frequency, because it has high avalanche electric field and good electron transport characteristic. Although the GaN-based HEMT has high avalanche electric field, the GaN-based HEMT is easily damage by the electrostatic discharge (ESD), when the device is under test by the ESD.To solve this problem that the GaN-based HEMT is easily damage by the ESD, the mechanism of the AlGaN/GaN HEMT is studied to explore a GaN-based ESD protection device in this paper. The protection device has a flexible control voltage and can be integrated in the AlGaN/GaN HEMT with a good compatibility in the process The main research in this paper as follow:1. The mechanism of the AlGaN/GaN HEMT is studied in this paper, including the polarization and the two-dimensional electron gas. The mechanism of the short-channel single-gate device is studied in this paper, including the relationship between the conduction band under the gate channel, the drain voltage, and the gate length. The shifting of the threshold voltage in the AlGaN/GaN HEMT is studied in this paper. A GaN-based device with the short channel effect to operate it to work is explored in this paper.2. The physical model of the TCAD-Sentaurus device simulation software for simulating the AlGaN/GaN HEMT is analyzed. The electrostatic discharge model is analyzed3. The unidirectional GaN-based ESD protection device is studied, the mechanism of this device is that the forward conduction and the reverse blocking of the device are achieved by the Schottky barrier in the anode. The study of this device shows that, the forward current of the device is related to the anode area, the anode-cathode spacing, and the Al composition in the AlGaN layer.4. An AlGaN/GaN high electron mobility transistor (HEMT) with bidirectional trigger is proposed. The concept of bidirectional trigger is that, the device is ON-state while the drain is biased with a certain voltage, or while the source is biased with a certain voltage. This trigger mechanism is attributed to the drain-induced barrier lowering effect (DIBL) generating under channel, while the drain or the source is biased with a certain voltage. The conduction band is led bending below the Fermi level by the DIBL, then the channel is punching-through, and the device is into conduction. The threshold voltage is related to the length of the gate by analyzing the trigger volge and the current characteristics of this device, while the L is shorter, the threshold voltage is the smaller.In a word, an AlGaN/GaN ESD protection device with bidirectional trigger is proposed, and the DC characteristics of this device are successfully simulated for verifying the characteristics of it.