A new high-voltage analog-compatible I/SUP 2/L process

A new technique for realizing high-performance I/SUP 2/L circuits simultaneously with high-voltage analog circuits is described. The method is flexible and may be used with any standard linear bipolar process. Only one additional noncritical masking step and one phosphorus implant are required to form the I/SUP 2/L n-wells. Experimental results are presented which show I/SUP 2/L betas of greater than eight per collector with the I/SUP 2/L BV/SUB CEO/ exceeding 3 V. The measured minimum average propagation delay is 40 ns using a 14 /spl mu/m thick, 5 /spl Omega/.cm epitaxial layer, while the analog BV/SUB CEO/ exceeds 50 V.     

Process and device performance of 1 /spl mu/m channel n-well CMOS technology

The process and device performance of 1 /spl mu/m-channel n-well CMOS have been characterized in terms of substrate resistivities of 40 and 10 /spl Omega/-cm, substrate materials with and without an epitaxial layer, n-well surface concentrations ranging from 5/spl times/10/SUP 15/ to 4/spl times/10/SUP 16/ cm/SUP -3/, n-well depths of 3, 4, and 5 /spl mu/m, channel boron implantation doses from 2/spl times/10/SUP 11/ to 1.3/spl times/10/SUP 12/ cm/SUP -2/, and effective channel lengths down to 0.6 /spl mu/m. Based on the experimental results obtained from /spl mu/m-channel n-well CMOS devices, the scaling effects on device and circuit performance of 0.5 /spl mu/m-channel n-well CMOS are discussed and the deep-trench-isolated CMOS structure is demonstrated.     

Planar GaAs IC technology: Applications for digital LSI

This technology utilizes multiple localized ion implantations directly into semi-insulating GaAs substrates, with unimplanted areas providing isolation between circuit elements. This approach allows for high yield, high density circuits, with optimization of various types of devices (e.g., GaAs MESFETs, high-speed Schottky-barrier diodes, etc.) made possible by optimizing the implantation profile for each type of device. The application of this fabrication technology for high-speed, ultra low power digital integrated circuits using a new circuit approach called Schottky diode-FET logic (SDFL) is described. Experimental GaAS SDFL logic ICs with LSI/VLSI compatible power levels (200-500 /spl mu/W/gate) and circuit densities (<10/SUP -3/ mm/SUP 2//gate) have been fabricated.     

I/SUP 2/L with a self-aligned double-diffused injector

Reports the structure topology, and characterization of integrated injection logic (I/SUP 2/L/MTL) with a self-aligned double-diffused injector. It is shown that using the new structure, a lateral p-n-p transistor with effective submicron base width can be realized even by using standard photolithographic techniques. One of the features of the approach is the high injection efficiency. Another feature is the high current gain capability for n-p-n transistors. A power delay product of 0.06 pJ, a propagation delay time of 10 ns at the power dissipation of 80 /spl mu/W, and a packing density of 420 gates/mm/SUP 2/ have been obtained by single layer interconnections of 6 /spl mu/m details. A J-K flip-flop with clear and preset terminals has been fabricated to demonstrate the superiority of S/SUP 2/L to conventional I/SUP 2/L.     

Injection-coupled memory: A high-density static bipolar memory

The design of a new static bipolar memory comparable with dynamic FET storages in density, but superior in performance and power dissipation is discussed. The concept of direct minority carrier injection is utilized for both the cell current supply and the coupling to the read/write lines. This has led to an extremely high degree of device integration resulting in a cell size of 3.1 mil/SUP 2/ using a standard buried layer process with 5-/spl mu/ line dimensions and single layer metallization. Investigations on exploratory chips containing small arrays have fully verified the feasibility. The cells have been operated at an extremely small d.c. standby power of below 100 nW. For a 4K b chip of about 160/spl times/150 mil/SUP 2/, an access time around 50 ns can be projected from the measurements simulating a 64/spl times/64 bit array. An extrapolation of the memory cell layout with oxide isolation and self-aligned N/SUP +/ contacts has resulted in a 1.1-mil/SUP 2/ cell with 5-/spl mu/ line dimensions.     

Poly I/SUP 2/L-a high-speed linear-compatible structure

Poly I/SUP 2/L a new bipolar process technology, is presented featuring 5 ns minimum propagation delay, 24 MHz flip-flop operation (using 10 /spl mu/ minimum feature size), and 15-30 V isolated and unconstrained linear circuit transistors on 5 /spl Omega/.cm epitaxy. Standard linear integrated circuit process complexity is increased by only one mask without extra diffusions.     

Integrated injection logic: a new approach to LSI

Multicollector transistors fed by carrier injection are used. A simplified (five masks) standard bipolar process is used resulting in a packing density of 400 gates/mm/SUP 2/ with interconnection widths and spacings of 5 /spl mu/m. The power-delay time product is 0.4 pJ per gate. An additional advantage is a very low supply voltage (less than 1 V). This, combined with the possibility of choosing the current level within several decades enables use in very low-power applications. With a normal seven-mask technology, analog circuitry has been combined with integrated injection logic (I/SUP 2/L).     

Low-temperature poly-SiGe alloy growth of high gain/speed pin infrared photosensor with gold-induced lateral crystallization (Au-ILC)

The hydrogenated poly-silicon germanium (poly-SiGe:H) epitaxial film has been investigated using gold-induced lateral crystallization (Au-ILC) technology on a-SiGe:H layers at 10-h 350/spl deg/C annealing temperature and 60-sccm hydrogen (H/sub 2/) content. Using this optimal condition, the growth rate of the induced Au was as large as 15.9 /spl mu/m/h. With a low annealing temperature (/spl les/400/spl deg/C) and large growth rate, this novel technology will be noticeably useful for poly-SiGe:H pin IR-sensing fabrication on a conventional precoated indium tin oxide (ITO)-glass substrate. Under a 1-/spl mu/W IR-LED incident light (with peak wave length at 710 nm) and at a 5-V biased voltage, the poly-SiGe:H pin IR sensor developed by the Au-ILC technology, i.e., an Al (anode)/n poly-SiGe:H/i poly-SiGe:H/p poly-SiGe:H/ITO (cathode)/glass-substrate structure allowed for maximum optical gain and response speed. The optical gains and the response speeds were almost 600 and 130%, respectively, better than that of a traditional pin type. Meanwhile, the FWHM of a poly-SiGe:H pin sensor with Au-ILC technology was reduced from 280 to 150 nm. This reveals excellent IR-sensing selectivity. These IR-sensing trials demonstrated again that the proposed Au-ILC technology has very useful application in the field of low cost integrated circuits on optoelectronic applications.     

A 3.5-ns, 2-W, 20-mm/SUP 2/, 16-kbit ECL bipolar RAM

A 3.5-ns emitter-coupled logic (ECL) 16-kbit bipolar RAM with a power dissipation of 2 W, a cell size of 495 /spl mu/m/SUP 2/, and a chip size of 20 mm/SUP 2/ has been developed. High performance is achieved using a high-speed Schottky barrier diode decoder with a pull-up circuit and a double-stage discharge circuit for a word-line driver. Small cell size is obtained using ultra-thin Ta/SUB 2/O/SUB 5/ film capacitors and 1-/spl mu/m U-groove isolation technology. An access time of 3.5 ns in this 16-kb bipolar RAM is equivalent to an effective access time of 2.5 ns at the system level, due to an on-chip address buffer and latch.     

A 1.0-ns 5-kbit ECL RAM

A bipolar 512/spl times/10-bit emitter-coupled logic (ECL) RAM with an access time of 1.0 ns and a power dissipation of 2.4 W, achieving an access-time power/bit product of 0.48 pJ/bit, has been developed. The RAM was fabricated using an advanced bipolar technology featuring poly-base self-alignment, poly-emitter shallow profile, and silicon-filled trench isolation with a minimum mask dimension of 1.2 /spl mu/m. A Schottky-clamped multiemitter cell with a cell size of 760 /spl mu/m/SUP 2/ is obtained as a result of compact cell layout and the use of 1.2-/spl mu/m trench isolation.     

A metallisation providing two levels of interconnect for beam-leaded silicon integrated circuits

A two-level-metal structure is described for beam-leaded silicon integrated circuits. The two-level structure consists of a Ti-Pt first level, plasma-deposited silicon nitride as interlevel dielectric, and Ti-Pt-Au as a second level. The Ti-Pt layers of both levels are sputter deposited. Sputter etching is used for pattern definition of the Pt layer of the first level and the Pt-Au layers of the second level. Two examples are presented of the application of the structure to bipolar integrated circuits. One is a LSI circuit consisting of a 24/spl times/9-bit sequential access memory implemented in a Schottky I/SUP 2/L technology and the other is a seven-gate inverter implemented in a standard buried collector technology.     

A high speed bulk CMOS C/SUP 2/L microprocessor

The CDP 1802, single-chip, 8-bit microprocessor is fabricated in C/SUP 2/L, or closed COS/MOS logic, a new structural approach to high-speed bulk silicon COS/MOS logic. In this self-aligned silicon-gate CMOS technology, the gate completely surrounds the drain providing transistor aspect ratios which maximize the transconductance to capacitance ratio and thus allow high on-chip speed. Generally, standard 6-/spl mu/m channel length C/SUP 2/L devices show an improvement in packing density by a factor of 3 over standard CMOS and operate at frequencies approximately four times faster than standard CMOS. High density 5-/spl mu/m channel length devices further improve area and speed by factors up to 1.5. The fabrication sequence for C/SUP 2/L devices requires six photomasks (one less than standard CMOS).     

Current hogging injection logic-a new logic with high functional density

A new design concept for bipolar integrated circuits with high functional density will be presented. The basic current hogging injection logic (CHIL) gate consists of a lateral intermediate collector structure, where the last collector simultaneously forms the base region of an inversely operated vertical output transistor. Thus a CHIL gate can be looked at as a CHL gate with a functionally integrated output transistor, or as an integrated injection logic (I/SUP 2/L) inverter with controlled injection. Dc and pulse measurements are discussed and calculated results with a simple model suitable for computer-aided design (CAD) are presented. The static noise immunity of CHIL circuits is compared to CHL and I/SUP 2/L. CHIL circuits are well suitable for large-scale integration (LSI) and are technologically compatible to all circuits fabricated in a standard buried collector (SBC) process.     

A 4-Mbit DRAM with half-internal-voltage bit-line precharge

A single 5-V supply 4-Mb dynamic random access memory (DRAM) was developed by using a buried-storage-electrode memory cell, a half-internal-voltage bit-line precharge method combined with a constant voltage converter, and a high signal-to-noise ratio sensing scheme. The chip was designed in a double-polycide, single-Al, epitaxial substrate NMOS technology with a 0.8-/spl mu/m minimum design rule. As a result, a 4M word/spl times/1-bit DRAM with 95-ns typical access time and 99.2-mm/SUP 2/ chip area was attained by 10.58-/spl mu/m/SUP 2/ storage cells.     

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.     

CMOS/SOS frequency synthesizer LSI circuit for spread spectrum communications

Using a 3.5-/spl mu/m gate length complementary metal-oxide-semiconductor/silicon-on-sapphire technology, a single-chip, radiation-hardened, direct digital frequency synthesizer has been developed. The circuit is a critical component of a fast-tuning wideband frequency synthesizer for spread spectrum satellite communications. During each clock period the chip generates a new digitized sample of a sine wave, whose frequency is variable in 2/SUP 20/ steps from DC to one-half the clock frequency. Operation at up to 7.5 MHz is possible in a worst-case environment, including ionizing radiation levels up to 3/spl times/10/SUP 5/ rads(Si). A computationally efficient algorithm was chosen, resulting in 12-bit output precision with only 1084 logic gates and 3840 bits of on-chip read-only memory. The accuracy of the algorithm is sufficient to maintain in-band spurious frequency components below -65 dBc. At 300 mW, the chip replaces an MSI implementation which uses 25 integrated circuits and consumes 3.5 W.     

Advancements in bipolar VLSI circuits and technologies

Due to their inherent speed advantage over FETs, bipolar circuits are widely used for high-performance masterslice and custom logic and for high-speed static memory arrays. For logic, traditional circuits such as transistor-transistor logic and emitter-coupled logic are still mostly used, but new circuit technologies such as integrated injection logic or merged transistor logic and Schottky transistor logic or integrated Schottky logic have been devised to manage the VLSI technology constraints. For high-speed memory applications such as caches, local stores, or registers, conventional memory cells are increasingly being replaced by more advanced memory devices allowing higher bit densities and lower power dissipation. Significant progress can be expected through technology extensions such as dielectric isolation, multilayer metallization, and polysilicon techniques, in addition to shrinking the devices to 1 /spl mu/m dimensions or below.     

Scaling I/SUP 2/L for VLSI

Scaling integrated injection logic for high-density VLSI circuits is discussed. The basic principles governing the operation of an I/SUP 2/L device and the impact of specific process/design changes on performance are reviewed. A procedure for scaling I/SUP 2/L devices with geometries >1 /spl mu/m is described and examples of scaled devices fabricated with e-beam slice writing techniques are given. It is shown that the I/SUP 2/L gate propagation delay can be scaled over the entire range of operating currents through a combination of scaling and sizing. The physical limitations that apply to submicron geometries are summarized and the performance attainable with a submicron device design is predicted.     

A monolithic 14 bit A/D converter

A 14 bit monolithic successive approximation A/D converter with 7 /spl mu/s conversion time is described. A special system called `dynamic element matching' is used to construct the high-accuracy D/A converter needed in the system. The high linearity of the converter (/spl plusmn//SUP 1///SUB 4/ LSB) results in an 84 dB S/N ratio. The high-speed comparator consists of a wide-band (75 MHz) clamped operational amplifier followed by a strobed flip-flop to freeze the output data. In the digital part, current mode logic (CML) is used for speed and low interference generation with respect to the analog circuitry. Digital input and outputs are TTL compatible. A low-noise, high-stability reference source with a temperature dependence of /spl plusmn/0.5 ppm//spl deg/C over -20 to +85/spl deg/C completes the A/D function. The chip is processed in a standard bipolar process using double layer interconnection. The die size is 3.5/spl times/4.4 mm/SUP 2/.     

A study on bipolar VLSI gate-arrays assuming four layers of metal

Describes a design study on a bipolar gate-array or masterslice chip with almost 10000 circuits. It assumes 2.5 /spl mu/m groundrules and four layers of metal, i.e. three layers of metal for global wiring and one layer for power and I/O redistribution. It is proven by using actual logic from the IBM 4331 system, that an additional wiring layer increases the circuit density on a masterslice chip by more than a factor of 2. The paper is divided into three sections. Section 1 describes the chip design, the detailed arrangement of internal and external cells with the associated wiring channels and some general aspects of a masterslice design. Section II explains the placement and wiring tools and gives detailed results of a wiring study, comparing a logic design with 2 wiring layers with the same logic implemented with 3 wiring layers (4 layers total). Section III covers the off-chip communication with its associated problems like noise generation by simultaneous driver switching, three-state driver, and embedded RAM macro testing.