Search results

The purpose of this study is to demonstrate a pseudomorphic High Electron Mobility Transistor (pHEMT) cutoff frequency (f_T) and maximum oscillation frequency (fmax) are determined by the role of its gate length (Lg). Theoretically, to obtain an Lg of 1 µm, the gate’s resist opening must be 1 µm wide. However, after the coat-expose-develop (C-E-D) process, the Lg became 13% larger after metal evaporation. This enlargement is due to both resist thickness and its profile.

This research aims to optimize the 1-µm Lg InGaAs-InAlAs pHEMT C-E-D process, where the diluted AZ®nLOF™ 2070 resist with AZ® EBR solvent technique has been used to solve the Lg enlargement problem. The dilution theoretically allows the changing of a resist thickness to different film thickness using the same coating parameters. Here, for getting a new resist, which is simply called AZ 0.5 µm, the experiment’s important parameters such as the coater’s spin speed of 3,000 rpm and soft bake at 110°C for 5 min are executed.

The newly mixed AZ 0.5 µm resist has presented a high resolution and undercut profile rather than standard AZ 1 µm resist. Hence, the Lg metallization after using AZ 0.5 µm optimized process showed better results than AZ 1 µm which used the standard process.

The outcome of the optimization has reached that it is possible to get a nearly sub-µm range gate’s opening using a diluted resist, and at the same time retaining a high resolution and undercut profile.

The purpose of this study is to show that due to the emergence of the Internet of Things (IoT) industry in recent years, the demand for the higher integration of wireless communication systems with a higher data rate of transmission capacity and lower power consumption has increased tremendously. The radio frequency power amplifier (PA) design is getting more challenging and crucial. A PA for a 2.45 GHz IoT application using 0.18 µm complementary metal oxide semiconductor (CMOS) technology is presented in this paper.

The design consists of two stages, the driver and output stage, where both use a single-stage common source transistor configuration. In view of performance, the PA can deliver more than 20 dB gain from 2.4 GHz to 2.5 GHz.

The maximum output power achieved by PA is 13.28 dBm. As the PA design is targeted for Bluetooth low energy (BLE) transmitter use, a minimum of 10 dBm output power should be achieved by PA to transmit the signal in BLE standard. The PA exhibits a constant output third-order interception point of 18 dBm before PA becomes saturated after 10 dBm output power. The PA shows a peak power added efficiency of 17.82% at the 13.24 dBm output power.

The PA design exhibits good linearity up to 10 dBm out the PA design exhibits good linearity up to 10 dBm output power without sacrificing efficiency. At the operating frequency of 2.45 GHz, the PA exhibits a stability k-factor, the value of more than 1; thus, the PA design is considered unconditional stable. Besides, the PA shows the s-parameters performance of –7.91 dB for S11, –11.07 dB for S22 and 21.5 dB for S21.