A three mask bipolar integrated circuit structure

A new bipolar integrated circuit structure has been fabricated that compares favorably to the MOS structure in terms of fabrication simplicity and performance. The new structure is basically a modified isolated lateral transistor and requires only three photolithographic masking operations up to and including first level of metalization. The fabrication of the structure is as follows: a shallow nonselective p-type base region is diffused into a lightly doped p-type substrate; n⁺emitter and collector regions are then simultaneously and selectively diffused into and through the p-type base region thus forming a lateral n-p-n transistor. The second and third masks define the contact holes and the metalization pattern, respectively. Lateral isolation of the structure is obtained by encircling the emitter and base regions with the collector region. Vertical isolation is achieved by the large collector-depletion region that extends beneath the emitter and base regions. Since the substrate is lightly doped a low collector voltage will adequately isolate the emitter and base regions from adjacent devices. The new technology permits the fabrication of transistors, resistors, and crossunders. Transistors with 2-to 3-µm spacings occupy 500 µm²of silicon area and have the following characteristics:beta = 35, peakf_{t} = 0.1GHz at 0.5 mA, BV(SUSTAIN) = 3 to 5 V,t_{r} = 20ns,t_{f} = 120ns,t_{s} = 20ns. Resistors with values as high as 40 kΩ have been fabricated within 600 µm². Active nonlinear loads with effective resistance up to 200 kΩ have been fabricated. TTL gates have been made with power-delay products of 3.6 pJ, and propagation delays of 34 ns.     

An isolated MISS regenerative switching device

A new MISS switching device structure was designed and fabricated, which consists of Al/thin thermal oxide/p-n⁺-p-Si layers and is isolated by diffusing n-well to the buried n⁺layer. Furthermore, an N⁺-shield layer which confines the carrier flow to the MIS interface and a p⁺-gate which injects carriers in the n⁺-p junction were successfully implemented. The device reveals that switching and holding voltages Vsand VHboth decrease with increasingA_{0x}, and with decreasingA_{J} and d_{0x}. The fringing effect is minimized due to the isolated structure.     

Second breakdown of double epitaxial transistors

This paper deals with the second breakdown of transistors with epitaxial collector, epitaxial base, and diffused emitter. Transistors were fabricated with base width WBin the range of 2 to 18 µ and resistivity in the range of 0.1 to 10 ohm . cm. The optimum values of the resistivity and the thickness of these regions were calculated by computer techniques. The devices were mounted onto a TO-63 header and the base and the emitter leads were bonded onto the device ultrasonically. The electrical characteristics, including the frequency response ftand secondary breakdownS/Bcapability, were tested. For the measurement of second breakdown current IM, forward bias condition was used. It was found that for fixed collector and emitter parameters, IMwas controlled by the product of base resistivity ρBand base width WB. The value of IMwas found to increase withrho_{B}W_{B}. However, for a specified device characteristic, an optimum value ofrho_{B}W_{B}was found to exist. For transistors withV_{CEO} =150volts,f_{t}=20mHz andh_{FE}=20, the optimum value ofrho_{B}W_{B}was found to be 6 × 10^-4ohm . cm².     

The temperature dependence of the DC base and collector currents in silicon bipolar transistors

Detailed measurements have been made of the base and collector-current characteristics of both n-p-n and p-n-p silicon transistors as a function of temperature. The collector current shows ideal behavior over the temperature range -60 to 150°C in thatI_{C} infin exp (eV_{BE}/kT). On the other hand, the base current is nonideal:I_{B} infin exp (eV_{BE}/nkT), wheren > 1.0. The nonideality of IBis the main source of the temperature dependence ofh_{FE} = I_{C}/I_{B}. There is no evidence for bandgap narrowing in the devices we have investigated. The temperature dependence of the collector current is given byI_{C} infin T_{m} exp (-e E_{g0}/kT) exp (eV_{BE}/kT), wherem = 1.4or 1.7 for n-p-n or p-n-p devices, respectively.E_{g0} = 1.19 pm 0.01eV. This result is consistent with the findings of others. The base current is a complicated function of temperature due to the presence of nonideal components.     

Higher dimensional orthogonal designs and applications

The concept of orthogonal design is extended to higher dimensions. A properg-dimensional design[d_{ijk cdots upsilon}]is defined as one in which all parallel(g-1)-dimensional layers, in any orientation parallel to a hyper plane, are uncorrelated. This is equivalent to the requirement thatd_{ijk cdots upsilon} in {0, pm x_{1}, cdots , pm x_{t} }, wherex_{1}, cdots , x_{t}are commuting variables, and thatsum_{p} sum_{q} sum_{r} cdots sum_{y} d_{pqr cdots ya} d_{pqr cdots yb} = left( sum_{t} s_{i}x_{i}^{2} right)^{g-1} delta ab,where(s{1}, cdots , s{t})are integers giving the occurrences ofpm x_{1}, cdots , pm x_{t}in each row and column (this is called the type(s_{1}, cdot ,s_{t})^{g-1})and(pqr cdots yz)represents all permutations of(ijk cdots upsilon). This extends an idea of Paul J. Shlichta, whose higher dimensional Hadamard matrices are special cases withx_{1}, cdots , x_{t} in {1,- 1}, (s_{1}, cdots, s_{t})=(g), and(sum_{t}s_{i}x_{i}^{2})=g. Another special case is higher dimensional weighing matrices of type(k)^{g}, which havex_{1}, cdots , x_{t} in {0,1,- 1}, (s_{1}, cdots, s_{t})=(k), and(sum_{t}s_{i}x_{i}^{2})=k. Shlichta found properg-dimensional Hadamard matrices of size(2^{t})^{g}. Proper orthogonal designs of type     

Stimulated Raman emission in infrared excited gases

Using the pressure dependence of absorption, absorption coefficients and detunings were measured for CO2pump lines and the strong fat infrared emission in optically pumped D2O. The P (32) CO2line was found to be detuned ∼1.5 GHz from the ν2band transitions6_{6}, 6_{5} rightarrow 5_{5}, 5_{4}. The resulting emission lines at 50.3 μm and 66 μm were found to be detuned from their respective transitions by about the same amount. On the basis of these measurements and gain estimates for the far infrared, the resulting emission lines are identified as stimulated Raman emission.     

Dual product constructions of Reed - Muller type codes (Corresp.)

Various linear and nonlinearR(r,m)codes having parameters(2^{m}, 2^{k}, 2^{m-r})withk=sum_{i=0}^{r}left(^{m}_{i}right)are constructed fromR(r,q)andR(r,p)codes,m=p+q. A dual construction forR(m-r,m)codes fromR(p-r,p)andR(q-r,q)codes is also presented,m=p+q. As a simple corollary we have that the number of nonequivalentR(r,m)codes is at least exponential in the length (forr>1). ForR(m-r,m)codes, the lower bound is doubly exponential in the length (forr>1).     

Method for plotting frequency cutoff measurements for GaAs varactor diodes

Frequency cutoff for GaAs varactor diodes of diffused-P⁺-n-epitaxial n⁺-substrate construction can be plotted so as to conveniently show dependence of diode cutoff as measured at 10 GHz on diode n-region thickness and substrate resistivity. The measured data fit a model for the diode where the zero bias junction capacitanceC_{j0}is in series with a junction resistance Rjthat is proportional to1/C_{j0}, and a resistance RXthat is constant. Rjis the resistance of the diode n-region and the p⁺-diffused region, and is primarily dependent on the n-region thickness. RXis dependent on diode spreading resistance, and varies with substrate resistivity. RXis about 1 Ω for usual substrate material.     

Multiple-burst error-correcting cyclic product codes (Corresp.)

LetCbe the cyclic product code ofpsingle parity check codes of relatively prime lengthsn_{1}, n_{2},cdots , n_{p} (n_{1} < n_{2} < cdots < n_{p}). It is proven thatCcan correct2^{P-2}+2^{p-3}-1bursts of lengthn_{1}, andlfloor(max{p+1, min{2^{p-s}+s-1,2^{p-s}+2^{p-s-1}}}-1)/2rfloorbursts of lengthn_{1}n_{2} cdots n_{s} (2leq s leq p-2). Forp=3this means thatCis double-burst-n_{1}-correcting. An efficient decoding algorithm is presented for this code.     

A low-voltage high-speed silicon photodiode with buried isolation region for short-haul optical-fiber communications

A new epitaxial silicon p-i-n photodiode has been developed for short-haul optical-fiber communications that can be operated at biases as low as 4 V. The device has a heavily doped 5-µm-thick p⁺⁺isolation-region between the p⁺substrate and the π-epitaxial layer. Fast rise and fall times (2 ns), and low leakage current (40 pA) result from the recombination and trapping of the minority-carrier electrons in the substrate. Experimental results on such an n⁺-π-p⁺⁺-p⁺device with 1.1-mm²photosensitive area and 25-µm epi-layer thickness show quantum efficiency of 80 percent at 825-nm wavelength.     

On the weight distribution of binary linear codes (Corresp.)

LetVbe a binary linear(n,k)-code defined by a check matrixHwith columnsh_{1}, cdots ,h_{n}, and leth(x) = 1ifx in {h_{1}, cdots , h_{n}, andh(x) = 0ifx in neq {h_{1}, cdots ,h_{n}}. A combinatorial argument relates the Walsh transform ofh(x)with the weight distributionA(i)of the codeVfor smalli(i< 7). This leads to another proof of the Plessith power moment identities fori < 7. This relation also provides a simple method for computing the weight distributionA(i)for smalli. The implementation of this method requires at most(n-k+ 1)2^{n-k}additions and subtractions,5.2^{n-k}multiplications, and2^{n-k}memory cells. The method may be very effective if there is an analytic expression for the characteristic Boolean functionh(x). This situation will be illustrated by several examples.     

Repeated use of codes which detect deception (Corresp.)

A senderAwants to sendNmessagesx_{i} = 1 , ldots ,N, chosen from a set containingMdifferent possible messages,M > N, to a receiverB. Everyx_{i}has to pass through the hands of a dishonest messengerC. ThereforeAandBagree on a mathematical transformationfand a secret parameter, or keyk, that will be used to produce the authenticatory_{i} = f(x_{i} , k ), which is sent together withx. The key is chosen at random from a set ofLelements.Cknowsfand can find all elements in the setG(x_{i},y_{i}) = {k|f(x_{i}, k) = y_{i}}given enough time and computer resources.Cwants to changex_{i} into x^{prime}withoutBsuspecting. This means thatCmust find the new anthenticatory^{prime} = f(x^{prime} , k). SinceG(x_{i},y_{i})can be found for any(x_{i},y_{i}), it is obvious thatCwill always succeed unlessG(x_{i},y_{i})contains more than one element. Here it is proved that the average probability of success forCis minimized if (a)G(x_{i}, y_{i})containsL^{(N-1)/N}elements and (b) each new known pair(x_{j}, y_{j})will diminish this set of solutions by a factor ofL^{-l/N}. The minimum average probability will then beL^{-l/N}.     

Charge analysis of transistor operation including delay effects

The charge control concept of transistor operation is extended to include delay effects in an accurate, yet tractable, way. Defining the transit time τtas the ratio of the excess base charge to the collector current, the transform of the transit time τt(s) is approximated bytau_{t}(1 + Stau_{D}), where τDis the delay time. For a one-dimensional, homogeneous-base transistor,tau_{D} = tau_{t}/6. The results of this technique are in good agreement with exact calculations.     

A study of the CW 28-µm water-vapor laser

The low signal gain of a CW water-vapor laser at 28 μm was measured as a function of the discharge current and pressure. Together with the measurement of other quantities such as the axial electric field and the concentration of OH, a partial interpretation of the mechanisms involved in pumping the 28-μm transition was possible. Thermal equilibrium between the ν0,2nu_{2}, and ν3vibrational levels will result in a large absorption at the elevated gas temperatures observed (800-1000 K). The strong dependence of gain on the electron temperature strongly suggests that the vibrational excitation proceeds through electron-impact excitation. Only the electron-impact excitation of H2O is quantitatively capable of overcoming the large thermally induced absorption. Although vibrational-excitation transfer from H2to H2O seems insufficient, by itself, to overcome this absorption, it may provide appreciable additional gain. Pumping of the 28-μm line through electron-ion recombination and by reactions involving OH can be ruled out.     

Recursive computations for the optimal tracking of time-varying parameters (Corresp.)

Recursive relations are given for updating the conditional densityp(theta_{k} | X_{k-1}, cdots X_{1})(also forp(theta_{k} | X_{k}, cdots, X_{1})), wheretheta_{k}is a parameter of the density ofX_{k}. The observationsX_{1}, X_{2}, cdotsare assumed to be conditionally independent (i.e., for known parameters), and the sequence of time-varying parameterstheta_{1}, theta_{2}, cdotsconstitutes a Markov-M sequence. The result requires the storage of an intermediate function of(theta_{k-1}, cdots , theta_{k-M}).     

Capacity theorems for the relay channel

A relay channel consists of an inputx_{l}, a relay outputy_{1}, a channel outputy, and a relay senderx_{2}(whose transmission is allowed to depend on the past symbolsy_{1}. The dependence of the received symbols upon the inputs is given byp(y,y_{1}|x_{1},x_{2}). The channel is assumed to be memoryless. In this paper the following capacity theorems are proved. 1)Ifyis a degraded form ofy_{1}, thenC : = : max !_{p(x_{1},x_{2})} min ,{I(X_{1},X_{2};Y), I(X_{1}; Y_{1}|X_{2})}. 2)Ify_{1}is a degraded form ofy, thenC : = : max !_{p(x_{1})} max_{x_{2}} I(X_{1};Y|x_{2}). 3)Ifp(y,y_{1}|x_{1},x_{2})is an arbitrary relay channel with feedback from(y,y_{1})to bothx_{1} and x_{2}, thenC: = : max_{p(x_{1},x_{2})} min ,{I(X_{1},X_{2};Y),I ,(X_{1};Y,Y_{1}|X_{2})}. 4)For a general relay channel,C : leq : max_{p(x_{1},x_{2})} min ,{I ,(X_{1}, X_{2};Y),I(X_{1};Y,Y_{1}|X_{2}). Superposition block Markov encoding is used to show achievability ofC, and converses are established. The capacities of the Gaussian relay channel and certain discrete relay channels are evaluated. Finally, an achievable lower bound to the capacity of the general relay channel is established.     

A simplified capless annealing of GaAs for MESFET applications

A simple capless annealing technique for post-implantation annealing of a GaAs wafer is described. The technique incorporates a novel boat design and uses InAs as the source of arsenic overpressure. Using this technique, wafers annealed at 850°C show mobilities in the range of 4000 cm². V^-1. S^-1with over 85-percent activation for a Si dose of5 times 10^{12}cm^-2. Dopant depth profiles with peak donor densities of2 times 10^{17}cm^-3and minimal tailing were demonstrated. Electron channeling data show that crystallinity is fully restored during the anneal. 1-µm gate length MESFET's processed on n⁺-n implanted layers exhibitedg_{m} geq 160mS/mm and pinchoff voltages in the range of 3 V.     

MBE grown n+-i-δ(p+)-i-n+GaAs V-groove barrier transistor

The three-terminal n⁺-i-δ(p⁺)-i-n⁺V-groove barrier transistor (VBT) has been successfully fabricated by molecular beam epitaxy (MBE). The base terminal is connected to the δ(p⁺), the thin p⁺layer, by depositing aluminum on the etched V-groove. The demonstrated device possesses high potential of ultra-high-frequency (f_{r} > 30-GHz), high-power, and low-noise capability due to carriers transporting by thermionic emission and being controlled by the base-emitter bias.