JPS5850769A - semiconductor storage device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on I'L (Integrated Inj
ectim Iogic). “A semiconductor memory that can only be read electrically Q
E (Read Qnly Memory) and RAM (Random Ac) which can be electrically rewritten.
Due to the pursuit of functions such as higher speed, lower power consumption, and greater integration, their structures and manufacturing processes are becoming more complex year by year. Most of these memories are MO8m, and in this case, it is relatively easy to construct a tcROM and RAM in an MO8 semiconductor chip and create a multifunctional chip such as a microcomputer. On the other hand, when configuring memory with a bipolar type that can be used at high output, if you are trying to pursue multiple functions in the same way, it is necessary to use Kti13L to save the chip size.
It is natural to consider using .

R and AMK systems using ItL are known as RK, but if you try to configure RQM with IIL, it will become complicated both in terms of structure and process.

General +) It cannot be easily created on a near IC, and such a ROM is 1! There are no reports of this occurring.

Therefore, conventionally, in bipolar polymorphic memory, R
AM and ROM are not included in the same system, and peripheral circuits are also formed on separate chips, making the memory device more complex and larger.

The present invention is to solve the above-mentioned problem, and its purpose is to solve the above-mentioned problem.
The purpose is to obtain memory cells for OM, and also.

F consisting of peripheral circuits and ILL operating in the same chip
Configuring LAM and R,OM.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Figures 1a and -ib show a plan view and a cross-sectional view of one cell of a ROM using I"L according to the present invention. In the figure, l is a p-118i substrate (substrate). , 2 is an N+m buried layer, 3 is an N-type epitaxial layer, and 4 is a pH injector.

5 is an NPN inverse transistor-Q.

Q, pm base, 6 is also an N+ collector.

7 is NWi engineering (ivy coloring). QA=Ql sandwiches the injector to form a pair of I''L, and connects it to the free lug frog as shown in Figure 2. βi (of QA and QB)
For example, the base region 5 of Ql has a difference in h during transistor operation (inverse NPN), so that βi of Q, is larger than IC βi of Q,
Deeper (formed) than that of A.

5 The cell CE,l consisting of the above pair of ItL connects its common injector terminal PI to the word line W as shown in FIG.
Connect to terminal P to both emitters E8 and Ebwo.
, and connect this to the reference potential. Furthermore, cell transistor Q4. Q.
tl) to bit lines BL1 and BL, respectively, to configure ftQM.

Next, the operation will be explained with reference to FIG. 3. For example, when the cell CEI is read out, the word line WL is
, (injector CPt point)), and on the other hand, the bit lines BL1 and B are raised by the Y decoder DY.
L, is coupled to the sense amplifier 8A. WL
By setting , to a high potential, a base current flows through QA and Ql, and a collector current ICAs multiplied by β1
"am" determines the sinking state of its base current.This is determined by the second collector CABec,
, through the lines BL1, BL! The current is sensed by eight sense amplifiers, and βi (QA)) βi
Since (Q, ), Q, , is in a state of ``sucking the base current of Q,'' and Ql with small β1 is cut off (
(see Figure 4), one current limiter, IR, has a current I
cA-proportional current, also current limiter IR.

A current proportional to the current lcl flows through the bit line BL, and the difference in this current is detected by the sense amplifier 8A.
Determine whether (or nL,) is logic "0" or "1." = , In this way, by creating a difference in the β of the pair I", L QA * QB, the basic cell of the ROM is configured. However, there are the following methods and methods for creating a difference in βi.
- (1) Of the IIL of the pair, as in the true example above.

The base depth is changed by implanting impurity ions into one of the inverse transistors. As shown in the 6th aalK, B (boron) ion implantation for Pfi base diffusion is performed twice on one side and once on the other side.

(2) Make one N+ type collaring deeper than the other. That is, in addition to P (IC) deposition for emitter diffusion, ion implantation is performed.

+3) Make the collector size of one inverse transistor different from the other.

(4) Fcp (phosphorous) ions are implanted into a portion of the Nfi epitaxial layer where one inverse transistor is to be formed.

(5) N+ where one inverse transistor is formed [PC17n in a part of the injection layer]! The "rising phenomenon" in the epitaxial layer is utilized by positive or ion implantation (see Figure 6b).

, (6) Lateral PNp,) Change the base width of the transistor, that is, the width between the injector and the base of the inverse NPN transistor ('ssd* in the JI6C diagram). Each PNP) rank, star, and base KP (phosphorus) are ion implanted. In other words, the injection efficiency is increased (see Figure 6c).

A highly integrated ROM memory with seven cells can be realized by I''L, which is more or less than the present invention-5 described in the embodiments above.

In the present invention, since the EtOM can be easily configured with KItL as described above, one peripheral circuit may be equivalent to a RAM, and thus a RAM and a ROM can be configured simultaneously in the memory area of the same chip. As shown in FIG. 5, on a chip 8, among a group of memory cells consisting of I"L, a ROM is constructed in a region 9 in which the basic cells are ILL of a pair with βi[difference, and there is no IiK difference. A RAM is constituted by an area 1-0 having a pair of IILs as basic cells.Peripheral circuits include an x-decoder 12, an x-decoder 12, and an x-decoder 13.

Like the RAM, it has a difference in βi and can be constructed using general I''L and normal transistors.

According to the present invention, KfLAM and fLOM were not included in the same system when the memory was configured with IIL, but by putting them in the same system, the peripheral circuits can be shared by the same system, for example, in the I"L microcomputer. RAM
It has become possible to reduce the chip size by allowing ROM to coexist. .

[Brief explanation of the drawing]

FIG. 1a is a plan view showing a basic cell of a ROM using a pair of IILs according to the present invention, and FIG.
-A sectional view, FIG. 2 is a circuit diagram of a ROM cell corresponding to FIG. 1a, and FIG. 3 is a ROM system diagram, and an enlarged view of a part thereof corresponds to FIG. 2. Fig. 4 is an output characteristic diagram of a pair of inverse transistors, Fig. 5 is a schematic layout diagram of an Ic memory device including peripheral circuits, and Figs. 6a to 6C are a method of creating a difference of βi in I''L of a pair. FIG. l...P-type substrate, 2...N''mMi layer, 3...
・N- type epitaxial layer, 4...: Pffi injector, 5... Ptl1 pace, 6... N+ type collector, 7... N+ m-type ivy coloring, 8...
Chip, 9...ft0M area, 10...RAM area, ll...Sense amplifier. 12...X decoder, 13...X decoder. Fig. 1α Fig. 1b Fig. 4 Fig. 5 Fig. 1 /3 Fig. 6 Fig. 6b Fig. 6C

Claims (1)

[Claims] 1. A pair of reverse transistors formed on a single semiconductor substrate is configured into a 7-lip-flop configuration, and information is written using the difference in current amplification factor (/i) of the pair of reverse transistors. 2.On one semiconductor substrate, a pair of I2L structure groups are formed, in which the current layer ratios of a pair of reverse transistors are different from each other, or the injector efficiencies for them are different from each other. "Other It'L" whose transistors have the same electrical characteristics
A structure group is formed, and RO is formed by the pair of ILL structure groups.
A semiconductor memory device which constitutes M and also constitutes a RAM by the other ILL structure group.