高散热变k介质埋层SOI高压功率器件

A Highly Heat-Dissipating SOI High Voltage Power Device with a Variable k Dielectric Buried Layer

针对常规SOI器件纵向耐压低和自热效应两个主要问题,提出了变k介质埋层SOI(variablekdielectricburiedlayerSOI,VkDSOI)高压功率器件新结构.该结构在高电场的漏端采用低k介质以增强埋层电场,在高电流密度的源端附近采用高热导率的氮化硅埋层,从而器件兼具耐高压和降低自热效应的优点.结果表明,对于k1=2,k2=7·5(Si3N4),漂移区厚2μm,埋层厚1μm的器件,埋层电场和器件耐压分别达212V/μm和255V,比相同厚度的常规SOI器件的埋层电场和耐压分别提高66%和43%,最高温度降低52%.

Aiming at two main problems of SOI device the low vertical breakdown voltage and self-heating effect a novel SOI high-voltage power device with a variable-k dielectric layer （VkD） is proposed. A low-k dielectric is used to enhance the electric field of the buried layer on the drain side with a high electric field,and a high-thermal conductivity dielectric is used near the source side where the current density is large. The device thus can sustain a high voltage while simultaneously reducing the self-heating effect simultaneously. The results show that an electric field in the buried layer of 212V/μm and a breakdown voltage of 255V can be obtained for a VkD structure with a 2μm-thick Si layer and a 1μm buried layer with low k 1 = 2. Compared with conventional SOI, the electric field of the buried layer and breakdown voltage of the VkD SOI are enhanced by 66% and 43% ,respectively. The maximum temperature of the device is lowered by 52%.