传统MOSFET和超结MOSFET的体二级管反向恢复特性评估  

Reverse Recovery Evaluation of Conventional and Super Junction MOSFET Body Diodes

作　　者：P.舍诺依 S.舍科哈瓦特 B.勃劳克威 刘茵[2] 

机构地区：[1]飞兆半导体公司,芒谭陶浦美国pa18707 [2]清华大学电力电子厂

出　　处：《电气技术》2006年第9期86-89,共4页Electrical Engineering

摘　　要：在许多高电压开关应用当中,都需要采用具有良好特性的体二极管且耐用性强的MOSFET。依照超结(SJ)电荷平衡概念所设计的器件,由于有着比普通MOSFET低得多的Rdson而得到普及。然而,普通sJ器件的一个缺点就是它的体二极管的反向恢复特性较差。早期的sJ器件有着较大的反向恢复电流,并且在某些反向恢复的情况下易于失效。尽管后来它的体二极管特性有了一定改善,但还是不能像传统MOSFET的体二极管那样耐用。我们示出即使施加缓和上升的di/dt,普通SJ器件的体二极管也还会失效。飞兆(Fairchild)公司利用二维数字仿真在电路和器件混合建模的条件来分析反向恢复瞬态期间在器件的内部发生了什么。这帮助我们理解失效背后的原因,并且设计出了耐用性更强的SuperFETTMSJ器件。反向恢复测量表明,普通SJ器件的体二极管在di/dt仅为100A/μs的时候就会失效,而SuperFETTM器件几乎是不会破坏的,它在di/dt为1000A/μs时仍能工作。飞兆(Fairchild)公司还设计出了带有快速恢复体二极管的、耐用的SuperFETTM器件,具有较低的Trr和Qrr。MOSFETs with good body diode characteristics and ruggedness are needed in manyhigh voltage switching applications. Super junction (SJ) charge balance concept devices[1,2] are gaining popularity as they have much lower Rdson compared to regular MOSFETs. However ,one draw back of SJ devices has been the poor body diode reverse recovery characteristics. Early generation SJ devices had high reverse recovery current and failed during some reverse recovery events. Even though the body diode characteristics have improved over time, they are still not as rugged as conventional MOSFET body diodes. We show that competition SJ device body diodes fail during moderate di/dt conditions. Fairchild has used two dimensional numerical simulations in mixed mode circuit and device conditions to analyze what is happening inside the device during the reverse recovery transient. This has helped us understand the reasons behind the failure and have designed a rugged SuperFETTM SJ device. Reverse recovery measurements show that competitors SJ MOSFET body diodes fail at a di/dt of just 100A/us where as SuperFETTMdevices are virtually indestructible, surviving >1000A/us.Fairchild has also introduced rugged superFETTM devices with fast recovery body diodes which have low Trr and Qrr.

关 键 词：体二极管 反向恢复特性 耐用性 超结M0SFET 

分 类 号：TN31[电子电信—物理电子学]