Showing papers in "Journal of Semiconductor Technology and Science in 2019"
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TL;DR: In this article, an AlGaN/GaN heterojunction phototransistor with a recessed detection area was developed to enhance the photoresponsivity, which achieved a 1.6 × 107 A/W at 375 ㎚.
Abstract: We developed an AlGaN/GaN heterojunction phototransistor with a recessed detection area to enhance the photoresponsivity. The recessed-AlGaN/GaN phototransistor exhibited a maximum photoresponsivity of 1.6 × 107 A/W at 375 ㎚, which was ~30% higher than that obtained with a conventional AlGaN/GaN phototransistor. A comparable photoresponsivity was also achieved at 260 ㎚ in UV-C range due to the dual absorption process in conjunction with the polarization induced built-in electric field characteristics of AlGaN/GaN heterojunction.
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TL;DR: This paper presents a fully differential implantable neural recording front-end IC for monitoring neural activities that consists of a low-noise amplifier, a variable gain amplifier, and a buffer.
Abstract: This paper presents a fully differential implantable neural recording front-end IC for monitoring neural activities. Each analog front-end (AFE) consists of a low-noise amplifier (LNA), a variable gain amplifier (VGA), and a buffer. The output signal of the AFE is digitized through a successive approximation register analog-to-digital converter (SAR ADC). The LNA adopts the currentreuse technique to improve the current efficiency, achieving the power consumption as low as 0.95 μW. The implemented LNA has the gain of 40 dB, the lowpass cutoff frequency of 10 kHz, and the high-pass cutoff frequency of sub-1 Hz which is realized using the current-controlled pseudoresistor. The VGA controls the gain from 21.9 dB to 33.9 dB for efficient digitization while consuming the power of 0.35 μW. The buffer drives the capacitive DAC of the ADC and consumes the power of 3.28 μW. The fabricated AFE occupies the area of 0.11 ㎟/Channel and consumes 4.6 μW/Channel under 1-V supply voltage. Each channel achieves the input-referred noise of 2.88 μVrms, the NEF of 2.38, and the NEF²VDD of 5.67. The front-end IC is implemented in a standard 1P6M 0.18-mm CMOS process.
TL;DR: In this article, the authors proposed a 3D test methodology for multi-axis MEMS gyroscopes based on the coordinates transformation, which was validated experimentally using a three-axis MIMO gyroscope from ST Microelectronics.
Abstract: Recently, the demand for micro-electromechanical systems (MEMS) based inertial sensors has been increased due to a wide range of application in consumer electronics; however, high volume production remains a major challenge for the MEMS industry. This paper proposes a new three dimensional (3-D) test methodology for the time-efficient evaluation of multi-axis MEMS gyroscopes. A mathematical model for the proposed 3-D test method was derived based on the coordinates transformation. The 3-D test methodology was validated experimentally using three-axis MEMS gyroscope from ST Microelectronics and the results were compared with the conventional one dimensional (1-D) test method. The experimental results revealed that the measurement error between the conventional 1-D and the proposed 3-D test was less than 1%, whereas the test time was decreased three times. Finally, the error sources and limitations of the proposed 3-D test method was highlighted.