摘要
针对薄外延横向功率集成技术的发展,提出一种降低体内电场REBULF(REducedBULkField)的新耐压技术,并设计了一例具有n+浮空层的REBULFLDMOS新结构.新耐压机理是通过嵌入在高阻衬底中的n+浮空层的等电位调制作用,提高源端体内低电场而降低漏端体内高电场使纵向电场重新分配,同时使衬底耐压提高.借助二维数值分析,验证了满足REBULF的条件为n+层的位置与衬底浓度的乘积不大于1×1012cm-2;在保证低的比导通电阻条件下,新结构较传统LDMOS结构击穿电压可提高75%以上.
A novel REBULF （reduced bulk field） concept is proposed for the development of a smart power integrated circuit with a thin epitaxy layer,and a new REBULF LDMOS device structure is designed with an n^＋ -floating layer embedded in the high-resistance substrate. The mechanism of the improved breakdown characteristics is that a high electric field around the drain is reduced by a n^＋ -floating layer,which causes the redistribution of the bulk electric field in the drift region, and the substrate supports more biases. The critical condition of the REBULF, which is analyzed and validated by a 2D MEDICI simulator,is that the product of the location of the n^＋ -floating layer and the substrate doping cannot exceed 1 × 10^12cm^-2. The breakdown voltage of the REBULF LDMOS is 75% greater than that of a RESURF LDMOS.
基金
模拟集成电路国家重点实验室
国家自然科学基金(批准号:60576052)资助项目~~
