Bipolar IC Process Research Articles

A 14 Gbps On-/Off- Keying Modulator in GaAs HBT Technology

A proof of concept on-/off- keying (OOK) modulator is designed and implemented in a commercial heterojunction bipolar transistors IC process. The modulator circuit consists of an amplifier/latch structure, which is used as an OOK modulator for the first time. One of its advantages is that the topology may be implemented in both field effect transistor and bipolar technology. The measurement results correspond well with simulation and show that the modulator is capable of handling carrier frequencies up to 28 GHz, and data rates up to 14 Gbps. The isolation of the modulator in the off-state is better than 27 dB over the whole frequency range.

Antireflection Layer Coating for the Red Light Detecting si Photodiode

The effect of antireflection layer on the reduction of optical loss has been investigated in Si photodiodes detecting red light with central wavelength of 670 nm. The theoretical analysis showed minimum reflection loss of 6% for the thickness of about in the -Si system with the single antireflection layer and no reflection loss for the XNthickness of / in the -Si system with double antireflection layer. In our experiments, Si photodiodes with the web-patterned -shallow diffusion region were fabricated by bipolar IC process technology and the devices were classified into three kinds according to the structure of /antireflection layer. The fabricated devices showed maximum spectral response in the optical spectrum of 650∼700 nm. The average photocurrents of the devices with the thickness of /X, and under the incident power, of -17 dBm were 3.2 uA, 3.5 uA and 3.1 uA, respectively.

Integrated multi-environmental sensing-system for the intelligent data carrier

Abstract This paper deals with a monolithically integrated multi-sensor system for the intelligent data carrier (IDC) system. The system includes a three-dimensional accelerometer, pressure sensor, temperature sensor and humidity sensor as well as the peripheral circuitry for each sensor on one chip. The peripheral circuitry was designed to combine them to one-chip microprocessor with A/D converter. The monolithic multi-sensor chip was realized using an SOI wafer, where the Deep-RIE bulk-micromachining process and bipolar IC process were used for sensor device fabrication and circuit fabrication, respectively. The acquired data are logged on a nonvolatile memory and transmitted via TCP/IP protocol on the ethernet by the “embedded Linux board”. We also show the remote monitoring system for multi-environmental sensor by using the graphical software and general purpose web browsing software.

A wide-tunable translinear second-order oscillator

This paper describes the design and measurement of a translinear second-order oscillator. The circuit is a direct implementation of a nonlinear second-order differential equation and follows from a recently developed synthesis method for dynamic translinear circuits. It comprises only two capacitors and a handful of bipolar transistors and can be instantaneously controlled over a very wide frequency range by only one control current, which indicates its suitability for spread-spectrum communications. Its total harmonic distortion can be made small by the design, which enables fully integrated transmitters. A semicustom test chip, fabricated in a standard 2-/spl mu/m, 7-GHz, bipolar IC process, operates from a single supply voltage, which can be as low as 2 V and oscillates over six decades of frequency with -31 dB total harmonic distortion.

A low-voltage ultra-low-power translinear integrator for audio filter applications

In this paper, the design and measurement of a l-V translinear integrator and its application in a controllable second-order lowpass filter for hearing instruments is presented. A semicustom version of the filter has been integrated in a standard 2-/spl mu/m, 7-GHz, bipolar IC process and operates at voltages down to 1 V, consumes only 6 /spl mu/A, and has a dynamic range of 57 dB for a total harmonic distortion below 2%. Its cutoff frequency is linearly adjustable in octaves from 1.6 to 8 kHz.

Process and device optimization of an analog complementary bipolar IC technology with 5.5-GHz f/sub T/ pnp transistors

An analog complementary bipolar IC process has been developed featuring 9.0-GHz f/sub T/ npn and 5.5-GHz f/sub T/ pnp transistors. Process conditions for emitter, base, and collector of pnp transistors are optimized in order to achieve the best performance tradeoff between current gain, Early voltage, and cutoff frequency. With the optimized process conditions, the H/sub FE//spl times/V/sub A/ of pnp transistors is 350 V with f/sub T/ of 5.5 GHz and f/sub max/ of 8.5 GHz. These high performance pnp transistors have been integrated into an existing 9.0-GHz f/sub T/ npn bipolar process without introducing excessive additional process complexity and manufacturing costs. In addition, Schottky diodes, p-channel junction FET's and laser wafer trimmable precision NiCr resistors have been integrated into the process to enhance analog circuit design capability. >

An integrated optical position-sensitive detector with digital output and error correction

An integrated optical position-sensitive detector (PSD) with digital output is presented. A novel interpolating analog-to-digital converter which is based on a sigma-delta converter, is applied to perform three operations simultaneously. These are: calculation of the relative position cancellation of errors, both optical and electrical; generation of a microprocessor-compatible digital output. The realized smart sensor is integrated in a standard bipolar IC process, and measures 6.5 mm × 2.5 mm.

A new wide-band input compensation for packaged analog and digital multigigabit IC's

Packaging of multigigabit IC's introduces an input series inductance due to the bondwire which has a dominant influence on the overall IC performance. This paper describes the design and implementation of a novel input compensation circuit that both reduces the effects of the series inductance and offers the possibility to use an external termination with different impedances. Furthermore, a detailed theoretical investigation into the performance of the circuit is presented. A 7.4 Gb/s D-type flip-flop and a 4.2-GHz, 35-dB gain amplifier have been realized in a commercial 1-/spl mu/m silicon bipolar IC process with an average f/sub T/ of 11 GHz, showing the good performance of the input circuit. >

Optimization of TiSi2 / n + ‐ Polysilicon Process for Applications to Polysilicon Emitter Bipolar Integrated Circuits

Structural and electrical properties of layers were characterized at various process conditions. It was concluded that the high temperature silicide anneal must be kept below 850°C in order to maintain the integrity of the film and uniformity of the interface. A high temperature anneal at 800°C for 30 min was sufficient to produce the low resistivity C‐54 phase films. Maximum arsenic dose in the polysilicon layer was limited to to insure formation of thick and uniform films. An additional arsenic implant into the film before the high temperature anneal at 800°C was necessary in order to reduce the to n+‐polysilicon contact resistance. A high performance 4‐bit analog to digital (A/D) converter has been successfully demonstrated using this optimized process as part of an advanced bipolar IC process.

An integrated 4-20 mA two-wire transmitter with intrinsic temperature sensing capability

An integrated two-wire transmitter which converts signals from temperature sensors, resistance temperature detectors (RTDs), and thermocouples into an industrial standard 4-20 mA output is discussed. This transmitter is unique in that it is a silicon temperature sensor with a standard output which also allows compensation for the cold junction of thermocouples. The device is p-i-n programmable to perform different functions of signal conditioning and has been implemented on a standard bipolar linear IC process. Measured samples of an experimental chip configured as an RTD-signal conditioner have shown an accuracy of 0.1% and a nonlinearity of 0.02%. As a temperature sensor over the range 0.85 degrees C, the TWT has been accurate within +or-1 degrees C.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Application of radiation-tolerant field oxides and passivation films to the bipolar IC process

By applying a double-layer oxide film as a field oxide, the radiation tolerance of n-p-n transistors is improved by one order of magnitude compared with conventional transistors. The buildup of interface states is affected by formation of passivation films, and interface-state buildup using the polymide resin PIQ is suppressed by one-fifth compared with that of inorganic passivation film. Even though irradiation temperature affects the buildup of the interface states, the current gain of an improved n-p-n transistor is sufficient to allow operation at 75 degrees C irradiation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Analysis, design, and performance of micropower circuits for a capacitive pressure sensor IC

An integrated circuit has been designed, built, and testing as part of a capacitive pressure transducer. High-accuracy compact micropower circuits utilizing a standard bipolar IC process without any special components or trimming are used. The key circuits for achieving this performance are a Schmitt trigger oscillator and a bandgap voltage reference. The sensor circuits consume 200 /spl mu/W at 3.5 V, can resolve capacitance changes of 300 p.p.m., measure temperature to /spl plusmn/0.1/spl deg/C over a limited temperature range, and presently occupy 4 mm/SUP 2/ on a 2 mm/spl times/6 mm implantable monolithic silicon pressure sensor. Further scaling of the sensor is discussed showing that a reduction of area by a factor of 4 is achievable.

A monolithic common-collector front-end optical preamplifier

A monolithic transimpedance preamplifier has been developed having a common-collector cascode configuration with shunt feedback, using an advanced bipolar IC process. The measured sensitivity was -35.0 dBm at 140 Mbit/s for an error rate of 10-9and a p-in photodiode responsivity of 0.5 A/W.

Integrated piezoresistive pressure sensor with both voltage and frequency output

An on-chip integrated piezoresistive pressure sensor with both voltage and frequency outputs has been developed. The sensor chip, having a size of 3 × 3.8 mm 2, was realized by the use of a standard bipolar IC process. The output voltage span is 1 to 4 V for a pressure range of 0 to 750 mmHg. The pressure sensitivity of the voltage output is 4 mV/mmHg. The non-linearity is less than 0.4 % of the full scale. The sensitivity of the frequency output is about 30 kHz for a 750 mmHg change in pressure. The output is in the T 2L level. The temperature coefficient of the sensitivity is less than 0.06%/°C in the temperature range −20 to 110 °C.

A new method for realizing JFETs and super B's in a standard bipolar IC process

A new method for the realization of p-channel JFETs is presented. It is based on the removal of thin silicon layers by repeated anodic oxidation and etching, allowing the shallow-n (SN) diffusion to penetrate deeper into the shallow-p (SP) region. JFETs with a thin channel are thus obtained with a high yield and good reproducibility.

An integrated pressure transducer for biomedical applications

A monolithic integrated-circuit piezoresistive pressure transducer featuring a high output signal (of the order of mV/mmHg), high stability (less than 05 mmHg/24 h) and low temperature coefficient (temperature coefficient of sensitivity less than 10 −4/°C) is presented. These features are achieved through careful design of the full bridge, the diaphragm and the on-chip amplifier. In addition to the conventional bipolar IC process, silicon anisotropic etch and stress-free package techniques have been used in fabricating the devices. Since the application set-up of the device is simple and inexpensive, widespread usage is also expected in areas other than biomedical applications.

A high precision micropower operational amplifier

An operational amplifier configuration implemented as a true micropower high precision op amp is described. It includes a well controlled and predictable DC biasing network that is insensitive to variations in temperature, supply voltages, and process. Also, it permits single supply operation. Excellent DC precision characteristics, comparable to or better than the very best precision op amps currently available, are realized yet at micropower levels. By simply increasing the biasing currents, a version of this design operates in general purpose applications without any degradation in its high precision characteristics. Thus, the AC performance levels of general purpose op amps are attained at a fraction of supply current. This device is fabricated using a standard bipolar IC process; an ion-implanted JFET is added to simplify biasing.

A bipolar monolithic analog-to-pulsewidth converter

A precision analog-to-pulsewidth converter has been achieved with pulsewidth modulation technique and new circuit designs applied to a standard bipolar monolithic IC process. The magnitude and polarity of the input Information are determined by the pulsewidth modulated output signal within 0.002-percent linearity error and \pm 10 PPM/°C full-scale and zero-scale drift at low conversion rate. Although the low-frequency noise in EC buffer limits the actual resolution of the converter to 13 bits, the externally connected Zener diode in EC output reduces the EC noise, and the resolution increases to 15 bits which is consistent with the linearity of the converter.