标题: | 以氧化镧/氧化铪堆叠式氧化层作为高功率氮化镓高电子迁移率电晶体之闸极氧化层研究 The Study of La2O3/HfO2 GaN MOS-HEMT for High Power Application |
作者: | 蓝伟诚 Lan, Wei-Cheng 张翼 马哲申 Chang, Edward-Yi Maa, Jer-Shen 光电系统研究所 |
关键字: | 氮化镓高电子迁移率电晶体;氧化铪;氧化镧;闸极氧化层;GaN MOS-HEMT;HfO2;La2O3;Gate dielectric |
公开日期: | 2014 |
摘要: | 近几年,氮化铝镓/氮化镓高电子迁移率电晶体在高功率应用上广受注目。然而在应用中,仍存在闸极漏电流以及高电压下造成的电流崩溃这两个现象影响着元件的表现及稳定度。部分的文献已经证明使用金属-绝缘体-半导体的闸极结构能够有效地降低闸极漏电流以及高电压下造成的电流崩溃。 因此,本研究使用氧化铪与氧化镧/氧化铪堆叠式氧化层结构来制作金属绝缘层氮化镓高电子迁移率电晶体,并与传统的氮化镓高电子迁移率电晶体做比较。在闸极漏电流的表现上,使用氧化铪作为金属绝缘层可以降低接近2~3个数量级的漏电流,而使用氧化镧/氧化铪堆叠式氧化层的金属绝缘层结构则能够降低近4个数量级的漏电流。在抑制高电压下电流崩溃方面,传统氮化镓高电子迁移率电晶体的最大汲极电流降低了21%,而使用氧化铪与氧化镧/氧化铪堆叠式氧化层作为金属绝缘层的氮化镓高电子迁移率电晶体则分别降低了7%与0.8%。另外,使用氧化镧/氧化铪堆叠式氧化层作为金属绝缘层的氮化镓高电子迁移率电晶体在其他的电性如最大汲极电流、临界电压、转导等亦都有不错的表现。除此之外,藉由电容的频散现象与迟滞效应的量测以及X光光电子能谱仪(XPS)分析也都得到不错的绝缘层沉积品质。 In recent years, AlGaN/GaN high electron mobility transistors (HEMTs) have been widely studied for high power applications. However their performance and reliability are limited by the gate leakage current and drain current degradation. The utilization of insulator to form metal-oxide-semiconductor (M-O-S) gate structures has shown remarkable improvements in reducing gate leakage current and suppressing current degradation. In this study, we developed two kinds of MOS-HEMTs by using HfO2 and La2O3/HfO2 stacks to compare the electric properties with conventional HEMT. The gate leakage current of HfO2 MOS-HEMT and La2O3/HfO2 MOS-HEMT are individually suppressed almost two and four orders of magnitude compared with conventional HEMTs in positive bias region. Moreover, the current degradation of MOS-HEMT with HfO2 (PDA at 500°C) and La2O3/HfO2 (PDA at 600°C) as gate insulator was only decreased 7% and 0.8% (conventional HEMT decreased 21%). Besides, other DC characteristics such as maximum drain current, threshold voltage and transconductance also exhibited good performance in La2O3/HfO2 MOS-HEMT after PDA at 600°C. Furthermore, we obtained good quality of insulator deposition as revealed by the frequency dispersion, hysteresis effect and X-ray Photoelectron Spectroscopy (XPS) analysis in this study. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT070158005 http://hdl.handle.net/11536/76295 |
显示于类别: | Thesis |