Pseudomorphic High Electron Mobility Transistor Microwave Monolithic Integrated Circuit Study

With rapid development of microwave communication technology, the demands for communication system is more and more higher. Radar, communication and warning system currently in effect is complex, cumbersome and expensive because of using mixed integrated circuits. So it is necessary that the micro-millimeter wave monolithic integrated circuit. pHEMT MMIC has some advantages beyond other MMIC in the frequency, power consumption and noise, and it is one of the most competitions in the fields of micro-millimeter wave monolithic integrated circuits and super-high velocity digit integrated circuits. The researches of pHEMT and its microwave monolithic integrated circuits in this paper are reported. Major contents are abstracted as following: 1. The evolved history of high electronic mobility transistor is given in detail. HIEMT applications are summarized in the micro-millimeter wave system such as satellite communication, automobile radar, and optical fiber communication. Some deficient aspects are discussed on HEMT and it MMIC according to domestic research current situation. 2. The detailed comparison is dealed between MIESFET and pHEMT. The theory of Two-Dimension Electronic Gas (2DEG) is introduced. The relation of material structure of pHEMT and 2DEG are summed up from the start of math-physic structure model. Finally the characteristic of pHEMT are described including current-voltage, capacity-voltage and small signal behavior. 3. The material growth, CAD and manufacturing process of pFIEMT engender direct influence on the rate of finished pHEMT M~vHC. This paper researches the manufacturing process emphasisly in the view of some limits. The representative manufacturing process of pHEMT and discussed such as mesa insulates process, electrode process, photoetching process, metal lift-off process passivation, and selective-wet etching process. Two special topic are founded on?A study of the selective gate recess etching technology and its effects on the microwave properties of pHEMT?and iNs passivation thickness effect on A1GaAs/InGaAs/GaAs pHEMT performance? and theirs results are given as follows: ?about the selective gate recess etching technology to pHEMT(GaAs/AIGaAs/InGaAs), we determined a suitable etchant system. When the Citric Acid : H202 : H20 is 3:1:100, and Solution temperature remains constant room temperature at 250C and agitates it mildly and uniformly, the computed etching velocity is 5 angstrom per second of GaAs and 0.14 angstrom per second of AlGaAs, the Selective ratio is about equal to 36. ?There are two results about iNs passivation thickness effect on AlGaAsIInGaAs/GaAs pHEMT performance? (1) In general, the frequency of pHEMT is decreased as the thickness of SiN passivation?increasing. But the curve is parted into two segments and there is a inflexion point at 0.2tm of SiNx thickness. When SiNx thickness is smaller than 0.2jtm, the cut-off frequency accords with the relation expression: fT(d)=13.5 e 2 ; When SiNx thickness is greater than 0.2tm, the cut-off frequency accords with the relation expression: fT(d)=1 1.8 e 6 (2) When SiNx thickness is greater than 0.2pm, the device is invalid because of the stress on the surface of material induced by SiNx passivation. 4. Low noise pHEMT is important in the micro-millimeter wave system. The paper introduces the method of electricity and structure design for low noise pI-IEMT. The method of...