硅基沉积氮化镓,碳化硅,III –V 族及其合金材料研究进展

硅基沉积氮化镓, 碳化硅, III-V 族及其合金材料是近年来的研究热点. 氮化镓, 碳化硅及其III-V 材料在光电子和电子元件领域有着广泛的应用.例如大功率, 高速器件, 大型激光器, 紫外探测器等等. 尽管硅基片具有低成本, 大的尺寸,和极好的电热导性能等优点, 硅基片仍没有成为氮化镓, 碳化硅及III – V 的主要沉积基片, 其原因在于硅基片与氮化镓, 碳化硅及III-V 材料之间的热膨胀系数和晶格常数之间的失配. 自从1998年, IBM 的课题组用分子外延方法在硅基片上沉积氮化镓, 并且成功地制备了氮化镓激光器之后, 硅基氮化镓的研究开始备受关注. 近年来的研究发现, 使用氧化铝和氮化铝镓作为过渡层. 硅基氮化镓的热应力及与硅基片之间的晶格失配可以明显降低.在 6英寸的(111) 取向的硅基片上用化学气相方法可以成功地沉积超过一个微米厚的无裂纹的单晶氮化镓. 德国的AZZURRO 公司成功地制备硅基片氮化镓的大功率的蓝色激光器. 美国的NITRINEX公司也生产了硅基氮化镓大功率电子元件. 超大功率的硅基氮化镓电子元件仍在研究中. 在2007年, 英国政府设立了一个固体照明器件的研究项目. 主要着手研究6英寸的硅基氮化镓激光器. 另一方面, 在过去的40年, 超大规模硅基CMOS 技术已有了长足的发展, 下一代低功耗高速逻辑电路要求低的驱动电流, 小的活门尺寸低于 30 nm 和快速反应性能. 这就要求器件通道材料具有很高的电子(或空穴)迁移率. III-V 材料, 例如InSb, InAs, 和InGaAs 具有电子迁移率高达 80000 cm2/VS. 它们将是下一代低于 30 nm 硅基CMOS 器件最好的候选材料. 在 2007 年美国DARPA/MTO 设立了一个研究项目来发展硅基 III-V材料器件, 着重于发展高速硅基III-V材料CMOS 器件. 第一届”硅基氮化镓,碳化硅,III-V及其合金材料研究进展 ”国际会议也将于3月 24日-28日在旧金山MRS 2008年初春季会议上召开.

Advances in GaN, SiC, III-V, and Related Alloys on Silicon Substrates

GaN, III-V, SiC and related alloys on Si substrates becomes a hot research area recently. GaN and SiC have wide applications in photonic and electronics, such as high power, high speed devices and LEDs UV detectors etc. Silicon substrates are low cost, available in large diameters and have well characterized electrical and thermal properties. Despite these advantages，silicon has not been popular as a substrate material for GaN, SiC and III-V growth due to several problems mainly related to the thermal and lattice mismatches. Silicon attracted attention as a substrate material for GaN growth when the first MBE grown GaN LED on Si was demonstrated in 1998 from IBM group. Recently. using AlN and AlGaN buffer layers for GaN and SiGe buffer layers for III-V materials growth on Si, the thermal stress and lattice mismatch can be reduced significantly and over 1µm crack free GaN epi-films can be grown on 6 inch Si(111) wafers. High power blue LED on Si have been demonstrated by AZZURRO, in Germany. The power devices on Si also have been made by Nitrinex in USA. The super high power devices on Si are still in instigation. In 2007, UK government set up a solid-state lighting program, which focus on developing GaN based LED on 6 inch Si substrates. On the other hand, continued physical scaling of mainstream silicon CMOS technology has boosted the performance of the Si devices in the past 40 years. Increasing the drive current at low-bias voltage to reduce the gate delay for 30 nm and beyond low-power logic application requires devices possessing channel materials with higher carrier mobility. III-V compounds with mobility as high as 80000 cm²/Vs are possible solutions for Si CMOS beyond 30nm，such as InSb, InAs, and InGaAs. In 2007, DARPA/MTO started a program for compound semiconductors on silicon (COSMOS) focusing on high speed chips embedded in silicon CMOS. The first international symposium deals with “Advances in GaN, GaAs, SiC and related alloy on Si substrates” in MRS 2008 spring meeting will be held on March 24 -28, 2008 in San Francisco, USA.