Research On The High-voltgae Lateral IGBT On Thick SOI

Single chip intelligent power ICs,integrating high-voltage power devices,level-shifter circuit and low-voltage logic circuits,is a high and low voltage compatible IC with high integration of functions and structures.Recently,the single chip intelligent power ICs,as the core component,have been widely used in the field of smart home appliance,new energy vehicles and intelligent robotics.Thick silicon on insulator(SOI)process owns low parasitic elements and excellent isolation performance.The high-voltage and low-voltage integration can be easily realized on the SOI process platform.The SOI lateral insulated gate bipolar transistor(SOI-LIGBT)used as the switching device is the key component in single chip intelligent power ICs.In this dissertation,the characteristics and ruggedness of SOI-LIGBTs in the off-state,the on-state and the switching process are systematically studied in depth.The research details achievements are concluded as follows.1.In the single chip intelligent power ICs,the high-voltage interconnection(HVI)is required to transfer the signal between the high-side and low-side SOI-LIGBTs.In order to prevent the device from the premature breakdown,the mechanism of the breakdown voltage degeneration caused by HVI is studied and a structure with dual trenches is proposed.By employing the dual trenches structure,the electric field crowding on the silicon surface is avoided.The experiments show that the dual trenches technology can fully shield the influence of HVI and the length of the silicon region beneath the HVI can be shortened by 66.7%.2.In order to shrink the chip size,the SOI-LIGBT with high current density is essential.A SOI-LIGBT with U-shaped channel is proposed.The electron current injected into the drift region is enhanced by using the U-shaped channel.Because the electron current is mainly flow on the silicon surface,the shortcomings of the conventional dual channel technology is overcome.The experiments show that the current density of the U-shaped channel SOI-LIGBT can be enhanced by 177%while the latch-up voltage large than 500V can be obtained.The U-shaped channel SOI-LIGBT can achieve a trade-off between breakdown voltage and specific on-reisitance better than state-of-the-art SOI-LIGBTs.3.The enhancement of the current density could cause the non-uniform behavior during the turn-off and the degrading of the short-circuit capability.In this dissertation,the non-uniform behavior of the multi-finger SOI-LIGBT during the turn-off is studied.It is found that the non-uniform depletion behavior caused by the edge trenches could lead to the non-uniform current distribution among the fingers during the turn-off.An improved structure with trenches arranged between the adjacent fingers is proposed and the improved structure can turn-off successfully at 450V.In addition,the short-circuit characteristics of the U-shaped channel SOI-LIGBT is studied.A U-shaped channel SOI-LIGBT with dual-trench gates is proposed.The short-circuit withstand time is prolonged by 49%at the current density of 590A/cm2.4.In order to reduce the power consumption of single chip intelligent power IC,a high turn-off speed technology with deep-oxide trench(DOT)arranged in the drift region is proposed.DOTs can help to block the high voltage and the length of N-drift region of the device can be significantly reduced.The experiments show that the turn-off loss of the SOI-LIGBT can be improved by 59.6%by adopting the DOT technology.A trade-off between turn-off time and current density better than state-of-the-art SOI-LIGBTs can be obtained.