Performance enhancement in a metal-insulator-semiconductor–like pseudomorphic transistor by utilizing an n −-GaAs/ n +-In0.2Ga0.8As two-layer structure

• Published in: Applied physics letters 1995-03, Vol.66 (12), p.1524-1526
• Main Authors: Liu, Wen-Chau, Hsu, Wei-Chou, Laih, Lih-Wen, Tsai, Jung-Hui, Lour, Wen-Shiung
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.113634

A high performance metal-insulator-semiconductor–like pseudomorphic field-effect transistor utilizing an n−-GaAs/n+-In0.2Ga0.8As two-layer structure was fabricated and demonstrated. The n−-GaAs layer is used as the Schottky contact layer whereas the n+-In0.2Ga0.8As quantum well is employed as the active channel. Due to the excellent properties of the InGaAs layer and carrier confinement effect at the In0.2Ga0.8As–GaAs heterointerface, the device under study shows the advantages of high breakdown voltage, high current capability, very large gate voltage swing for high transconductance operation, and ease of fabrication. For a 2×100 μm2 gate device, a breakdown voltage of 17.4 V, a maximum drain saturation current of 930 mA/mm, a maximum extrinsic transconductance of 230 mS/mm, and a very wide gate voltage range larger than 3 V with the extrinsic transconductance higher than 200 mS/mm are obtained. Therefore, the device has great potential for use in high speed, high power, and large input signal circuit applications.