The Temperature Characteristics And New Structures Of High-voltage C-sensefet

High-voltage Controllable C urrent Sense Field Effect Transistor(C-Sense FET) is a kind of innovational high- voltage power integrated devices for current sampling and self-powering in Smart Power Integrated C ircuit(SPIC). With the common drain of the main power switch device(Lateral Double-diffused MOS, LDMOS) in SPIC, the C-Sense FET functions as LDMOS current sampling and self-powering in SPIC. With a inserted surface gate, the C-Sense FET features a controllable sensing characteristic and a stable charging characteristic. Firstly, this paper introduces the basic structures, operating principle and related circuit application design. Meanwhile, the temperature characteristics are detailed analyzed from the two aspects of simulation and experiment on the last batch of tape-out samples, foreshadowing the actual application design. Furthermore, two important parameters of C-Sense FET, the sampling ratio K and the charging swing factor α, have been detailed analyzed and optimized in this paper. Moreover, aimed at improving the saturated zone constant c haracteristic of C-Sense FET, a variety of novel structures have been proposed, which feature the more ideal sensing region and charging region. Through these research results, it is expected to be able to contribute significantly to the more extensive application of C-Sense FET.The main contents contain the following parts:1. Describe the basic structure and operation principles of C-Sense FET, and then explain the breakdown characteristics and conduction characteristiss with the associated simulation tools. The two critical parameters, the sampling ratio K and charging swing factor α, have been fully discussed, which correspond to the linear zone and saturated zone of C-Sense FET I-V characteristics, respectively. It has been discussed about how to improve the sampling and charging characteristics. In addition, the design of application of C-Sense FET device is also introduced in this paper.2. Explore the temperature characteristics of the C-Sense FET device. A brief introduction about the basis of heat-related knowledge. The temperature characteristics of C-Sense FET have been exhaustively analyzed from the two aspects of simulation and experiment on the previous batch of C-Sense FET samples. The temperature experiment mainly focuses on the block characteristics and conduction characteristics of C-Sense FET, the simulation results agree well with the experiment results. The temperature characteristics of C-Sense FET are essential to the design of application.3. A variety of new structures have been proposed to improve the performance of C-Sense FET. The sampling characteristics of C-Sense FET are mainly affected by the conduction resistance of the linear zone, and optimization of the on-resistance will help to improve the accuracy of sampling, such as RESURF, trench and other structures. Meanwhile, the charging swing factor is mainly associated with the saturated zone, the smaller the charging swing factor, the ideal the saturated region. To some extent, due to the fact that the constant current characteristics of C-Sense FET is mainly determined by the JFET structure inside of it, measures which can improve the constant current performance of JFET can also contribute to reducing the charging swing factor of C-Sense FET. Beginning with the illustrious channel pinch-off mechanism, analyze the factors that affect the channel length modulation effect of JFET, propose a variety of new innovative structures, Single Variable junction depth JFET(SVJFET), Double Variable junction depth JFET(DVJFET), P/Si O2 buried layer JFET(PMJF ET), Single side Trench JFET(STJFET), Double side Trench JFET(DTJFET). Under the identical current level, the new structures are more desirable than the traditional structure on the output characteristics. In the best case, the charging swing factor is reduced from 24.697% to 1.644%.