Studies Of Lateral Super-junction LDMOS And Integrated Low-voltage Power Supplies

In order to solve the increasing tense energy issues,the energy consumption structures of world are changing continuously,and the ratio of electrical energy to terminal energy structure is increasing constantly.Served as an electrical energy transformation technology,power electronics can realize the transformation and control of electrical energy more efficiently.Power electronics is important to save energy,and closely matches the themes of environmental friendly and sustainable development in the present age.Advances in power electronics technology is inseparable from the development of power semiconductor devices.From the primitive power diodes,semi-controlled thyristor to the fully controlled MOSFET(Metal Oxide Semiconductor Field Effect Transistor)and IGBT(Insulated Gate Bipolar Transistor)devices,structures of the power semiconductor devices are developing with continuous innovations and the electrical properties are changing greatly.The MOSFET,which is the representative of the unipolar power devices,is widely applied due to its excellent switching performance.However,it exists a so-called‘Silicon Limit'relationship between the breakdown voltage and the specific on-resistance.The Super-Junction(SJ)theory breaks the‘Silicon Limit'and makes great achievements in vertical MOSFET devices.However,studies of SJ theory in lateral MOSFET devices are less,most of which focus on optimizing electric field distribution with thin(less than 1?m)SJ layers and few pay attention to that with thick(more than 1?m)SJ layers.Power Integrated Circuits(PIC),which integrates the power devices and the controlling,detecting and protecting circuits in the same chip,are developing rapidly.Since the voltage of power devices is high,while the voltages of the controlling,detecting and protecting circuits are low,it is meaningful to design an integrated power supply from the high voltage applied on the power devices.Prof.Xingbi Chen invented a novel smart power integrated technology and low-voltage power supplies,which provide a practicable power supply scheme for the afore-mentioned low-voltage integrated circuits.The original works of this paper are embodied in Chapter 2,Chapter 4,and Chapter5,separately.The content of innovative works are listed as below:1.Based on analyzing the Substrate Assisted Depletion(SAD)effect and curvature effect,this paper proposed a multiple doped layers compensated lateral super-junction MOSFET with thick SJ layer.The proposal optimizes the electric field distribution in drift region and makes it uniform.By using the idea of the proposed structure,a lateral SJ MOSFET,whose breakdown voltage is 410 V and specific on-resistance is 15.5 m?·cm~2,is realized on a 6?m thick SJ layer and verified by the 3-D simulated results.Compared with the other lateral SJ MOSFETs at the same breakdown voltage level,the proposed one owes an even lower specific on-resistance.The idea,both in structure and design rules,gives a guidance for the optimization of the electric field distribution in drift region with thick SJ layer.2.A two-level low-voltage power supply with self-clamped characteristic is proposed and experimented.The proposed power supply can realize two different low voltages from the high voltage applied on power device without any extra control signals and manufactured processes.The steady-state experimental results reveal that the power supply can realize two stabilized low voltages when the input voltage is changed between90 V and 150 V.Besides,output voltages of the power supply present a negative temperature coefficient according to the temperature experiments.The proposed power supply is easily integrated but with relatively low drive capability.As a result,the proposal could find potential application in some low-voltage integrated circuits with low power consumption,such as the gate-driven circuit of the high-side power devices in half-bridge circuits.3.A negative low-voltage power supply,whose reference is the anode voltage of IGBT device,is proposed and experimented.The power supply,which compose of a high-voltage junction terminal and a specially designed low-voltage output circuit,can transform the very high voltage changing between 500 V and 1500 V to a constant negative low voltage with the anode voltage of IGBT as reference.The power supply can be fully realized without changing any manufactured processes,and its output voltages can be adjusted by choosing different zener diodes.Apart from being successfully applied to an IGBT optimization,the proposed negative power supply could also be used to provide power supply for those gate-driven circuits of PMOS in some specific circuits.