The Use of Low Temperature AlInAs and GalnAs Lattice Matched to InP in the Fabrication of HBTs and HEMTs

Abstract

AllnAs and GalnAs lattice matched to InP and grown by MBE over a temperature range of 200 to 350*C (normal growth temperature of 500'C) has been used to enhance the device performance of inverted (where the donor layer lies below the channel) High Electron Mobility Transistors (HEMTs) and Heterojunction Bipolar Transistors (HBTs), respectively. We will show that an AlInAs spacer grown over a temperature range of 300 to 350'C and inserted between the AlInAs donor layer and GaInAs channel significantly reduces Si movement from the donor layer into the channel. This produces an inverted HEMT with a channel charge of 3.0x1012 cm-2 and mobility of 9131 cm 2 /V-s, as compared to the same HEMT with a spacer grown at 500 *C resulting in a channel charge of 2.3x1012 cm-2 and mobility of 4655 cm 2 /V-s. We will also show that a GaInAs spacer grown over a temperature range of 300 to 350*C and inserted between the AlInAs emitter and GalnAs base of an npn HBT significantly reduces Be movement from the base into the emitter, thereby allowing higher Be base dopings (up to Ix10 20 cm-3