AlGaAs／InGaAs功率PHEMT用异质材料的计算机优化与器件实验结果

Computer Optimization and Device Experimental Result of Hetero-Layer-Structures for AlGaAs/InGaAs Power PHEMT Application

借助一新的工艺模拟与异质器件模型用ＣＡＤ软件──ＰＯＳＥＳ（Ｐｏｉｓｓｏｎ－ＳｃｈｒｏｅｄｉｎｇｅｒＥｑｕａｔｉｏｎＳｏｌｖｅｒ），对以ＡｌＧａＡｓ／ＩｎＧａＡｓ异质结为基础的多种功率ＰＨＥＭＴ异质层结构系统（传统、单层与双层平面掺杂）进行了模拟与比较，确定出优化的双平面掺杂ＡｌＧａＡｓ／ＩｎＧａＡｓ功率ＰＨＥＭＴ异质结构参数，并结合器件几何结构参数的设定进行器件直流与微波特性的计算，用于指导材料生长与器件制造。采用常规的ＨＥＭＴ工艺进行ＡｌＧａＡｓ／ＩｎＧａＡｓ功率ＰＨＥＭＴ的实验研制。对栅长０．８μｍ、总栅宽１．６ｍｍ单胞器件的初步测试结果为：ＩＤｓｓ２５０～４５０ｍＡ／ｍｍ；ｇｍ０２５０～３２０ｍＳ／ｍｍ；Ｖｐ－２．０－２．５Ｖ；ＢＶＤＳ５～１２Ｖ。７ＧＨｚ下可获得最大１．６２Ｗ（功率密度１．０Ｗ／ｍｍ）的功率输出；最大功率附加效率（ＰＡＥ）达４７％。

Computer simulation of device performance comparison among three kinds of AlGaAs/InGaAs hetero-layer-structure systems (conventional, single-,and double-δ-doping structures) which are applicable to power psuedomorphic HEMTs had been made by using a new CAD program-POSES (PoissonSchroedinger Equation Solver)specially designed for process simulating and device modeling of heterojunction devices. The optimized hetero-layer-structure parameters for power PHEMTs with the double-δ-doped AlGaAs/InGaAs heterojunction have been determined. On the basis of the assumed geometrical structure parameters of the device, both DC and microwave performances are estimated. The results are very helpful for MBE material growth and device fabrication. Power AlGaAs/In GaAs PHEMT has been fabricated on MBE wafer with the optimized structure by using a standard HEMT process. Primal results measured on the devices,with 1.6 mm gate width and 0. 8 μm gate length are:Idss250-450 mA/mm;gm250-320 mS/mm ; Vp- 2.0-2. 5 V ; BVds 5-12 V. At 7 GHz, maximum output power of 1. 62 W (Corresponding to 1.0 W/mm gate width )and maximum PAE of 47% are obtained.