分子束外延生长赝配高电子迁移率超高速微结构功能材料里深中心识别

Deep centers investigations of P-HEMT functional materials of ultra-high-speed microstructures grown by MBE

应用深能级瞬态谱 (DLTS)技术研究分子束外延 (MBE)生长的highelectronmobilitytransistors (HEMT)和Pseudo morphichighelectronmobilitytransistors (P HEMT)结构深中心行为 .样品的DLTS谱表明 ,在HEMT和P HEMT结构的n AlGaAs层里存在着较大浓度 (10 1 5- 10 1 7cm- 3 )和俘获截面 (10 - 1 6cm2 )的近禁带中部电子陷阱 .它们可能与AlGaAs层的氧含量有关 .同时还观察到P HEMT结构晶格不匹配的AlGaAs InGaAs GaAs系统在AlGaAs里产生的应力引起DX中心 (与硅有关 )能级位置的有序移动 .其移动量可作为应力大小的一个判据 ,表明DLTS技术是定性识别此应力的可靠和简便的工具 .

The deep centers of high electron mobility transistor (HEMT) and pseudomorphic-HEMT (P-HEMT) functional materials of ultra-high-speed microstructures grown by MBE are investigated using deep level transient spectroscopy (DLTS) technique. DLTS spectra demonstrate that midgap states, having larger concentrations and capture cross sections, are measured in n-AlGaAs layers of HEMT and P-HEMT structures. These states may correlate strongly with oxygen content of n-AlGaAs layer. At the same time, one can observe that the movement of DX center is related to silicon impurity that is induced by the strain in AlGaAs layer of the mismatched AlGaAs/InGaAs/GaAs system of P-HEMT structure. The experimental results also show that DLTS technique may be a tool of optimization design of the practical devices.