微纳电子技术

开发出一种适用于3mm功率器件的新沟道结构的GaAs PHEMT外延材料。分析了提高电子迁移率的途径,讨论了InGaAs电子有效质量和In组分的关系,参考InP HEMT结构的迁移率和沟道电子有效质量推算了InGaAs沟道的In组分范围;通过计算沟道内二维量子态浓度和临界厚度设计了沟道厚度。在MBE生长过程中通过工艺调整改善了高In组分沟道的晶体质量和界面平整度,降低了散射概率,设计并生长了不同沟道In组分和厚度组合的GaAs PHEMT材料,根据霍尔测试结果进行微调后室温霍尔迁移率和二维电子气(2DEG)浓度分别达到9 080 cm2/(V·s)和3.61×1012 cm-2。3mm功放器件结果:输出功率为21dBm,29 GHz下功率增益为8 dB,饱和电流为400 mA/mm,最大跨导为800mS/mm。

A new channel structure GaAs PHEMT epitaxial material for 3 mm power devices was designed.The approach of enhancing the electronic mobility was analyzed,the relationship between the electronic effective mass and In composition of InGaAs was discussed,and the In composition range of InGaAs channel was calculated by referring to the mobility and channel electronic effective mass of the InP HEMT structure.Besides,the channel thickness was designed with the calculation of the 2D quantum state concentration in the channel and critical thickness.The crystal quality and interface smoothness of the channel with high In composition were improved by the technical modulation during the MBE growth process,and the scattering probability was reduced.The GaAs PHEMT materials with different combinations of the In composition and thickness of the channel were designed and grown.After the fine adjustment based on the Hall test results,the Hall mobility and2 D electron gas(2DEG)concentration reach9 080 cm2/(V·s)and3.61×1012 cm-2 at room temperature,respectively.The results of the 3 mm power amplifier show that the output power is 21 dBm,the power gain is 8 dB at 29 GHz,the saturation current is 400 mA/mm and the maximum transconductance is 800 mS/mm.