JPH02222963A - Photosensitive body of amorphous silicon system - Google Patents

Abstract

PURPOSE:To obtain good scratching resistance and to prevent image flowing by respectively specifying the content of hydrogen and fluorine and the content of fluorine in a surface reforming layer. CONSTITUTION:The photosensitive body 39 consists of a charge blocking layer 44 of an a-Si system to be provided at need on a drum-shaped supporting base body 41 consisting of Al, etc., a photoconductive layer 43 consisting of a-Si:H, F, and the surface reforming layer 45 consisting of a-C:H, F. The content of the hydrogen and fluorine in the surface reforming layer 45 consisting of the hydrogenated-fluorinated-amorphous carbon doped by at least one of group IIIa elements is specified to 5 to 40 atomic% and the content of the fluorine therein is specified to 1 to 30 atomic%. The scratching resistance is improved and the image flowing is prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electrophotographic photoreceptor.

(Background of the Invention) Conventionally, amorphous silicon (
In recent years, an electrophotographic photoreceptor using a-3t) as a matrix has been proposed.

Since such a-5i has so-called dangling bonds, amorphous hydrogenated silicon (a-5t: H) has been proposed (Unexamined Japanese Patent Publication No. 5
No. 4-78135, No. 54-86341), but the dark resistance is still not sufficient.

In addition, sufficient measures have been taken to date to ensure the chemical stability of the surface of photoreceptors with a-5i:H surface against deterioration caused by air and moisture over time, or by active substances generated by corona discharge. If the film is left untreated for more than one month, for example, it will be affected by moisture, the acceptance potential will drop significantly, image blurring will occur, and structural changes will occur due to light irradiation.

On the other hand, amorphous hydrogenated silicon carbide (hereinafter referred to as a-5
Marked as iC:H. ), its existence and manufacturing method are “
Phi 1. Magn.
It is known that the optical energy gap changes over a range of 1.6 to 2.8 eV depending on carbon t. However, there is a drawback that the long wavelength sensitivity becomes poor due to the widening of the band gap due to the inclusion of carbon.

Furthermore, by introducing fluorine, which is more negative than hydrogen, it is possible to greatly promote the elimination of dangling bonds, increase the doping effect of the doping agent, and increase mechanical strength and light irradiation stability.

An electrophotographic photoreceptor combining such a-5iC:H and a-5i:H has been proposed, for example, in Japanese Patent Application Laid-Open No. 192046/1983. In this technique, a −3j: H, F
a-3iC:H and/or a-
The 3iC:F layer is formed as a surface modification layer.

Furthermore, a-5iC as a surface modification layer for a-3i-based adverse photosensitive photosensitivity:
H, a-5iN:H, etc. have been used, but at present, image deletion occurs in high temperature and high humidity, and a drum heater is used to avoid the problem.

Also, a research report on the a-C surface modified layer is published in the Electrophotography Society Journal f! It is described in Vol. J27, No. WI1 (24), etc.

However, when the present inventor investigated the photoreceptor provided with the above-mentioned known surface-modified layer, it was found that even with the surface-modified layer, it was still not as effective as expected, and the Ill strength was insufficient. However, image deletion tends to occur, and it has not been possible to achieve both image deletion and scratch resistance.

(Object of the Invention) An object of the present invention is to provide an electrophotographic photoreceptor that can withstand repeated use, has good scratch resistance, and has both good scratch resistance and prevention of image deletion.

(Structure and Effects of the Invention) The object of the present invention described above is to dope a photoconductive layer made of at least hydrogenated and/or fluorinated amorphous silicon with at least one of group a elements. In an electrophotographic photoreceptor having a surface modified layer made of hydrogenated-fluorinated amorphous carbon, the content of hydrogen and fluorine in the surface modified layer is 5 to 40 atoa+%,
This can be achieved using an amorphous silicon photoreceptor having a fluorine content of 1 to 30 atom %.

The hydrogenated fluorinated amorphous carbon (a-C:H
,P,! A-8i: A mixed gas of hydrocarbon and fluorocarbon is used to attach a-8i (denoted as 1) onto the photoconductive layer consisting of H and F, and the gas temperature and the photoreceptor substrate temperature are relatively low, and the electron temperature is low. It is preferable to use a plasma CVD method using a high glow discharge.

Hydrocarbons used in the present invention include CH-CzH-C5Ha, C4H1o, CaHa-CsHs
, CaH, CJt, CsH, C, Ha, CsH, and fluorocarbons include CF4, CHF.
, ,C,FiCSF, etc. are used.

By controlling the flow rate ratio of these gases, a-
C: Scratch resistance is improved by controlling the composition of H and F to be as follows.

Note that the above range also includes cases where the hydrogen content is O. Further, atom% is a percentage based on the number of atoms of an element.

Furthermore, B, Al1. G all n, 1O-3 to TI in the surface modification layer using at least one of the two elements as a doping agent.
Image deletion can be prevented by adding io4 volume ppm.

The doping agent may also be added to the photoconductive layer of a-5f:H, P according to the present invention in an amount of 10-3 to 10' volume ppm.

In addition to glow discharge plasma, techniques such as ion implantation may be used for doping.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 illustrates an A-3II electrophotographic photoreceptor 39 according to an embodiment of the present invention. This photoreceptor 39 has an a-5i charge blocking layer 44 provided as necessary on a drum-shaped conductive support substrate 41 such as AQ, and an a-8i:
It consists of a photoconductive layer 43 made of H, F, and an a-C:H, F surface modification layer.

The charge blocking layer 44 is a-5f:H, a-9jC
:H or a-5iN:I (and may be doped with an element of Group 1Na or Group Va of the periodic table. In addition, the photoconductive layer 43 may also be doped with a similar element. Good. The photoconductive layer 43 has a ratio of resistivity P in the dark and resistivity 1'L when irradiated with light, which is sufficiently large as an electrophotographic photoreceptor and has photosensitivity (particularly to light in the visible and infrared regions). is good.

The feature of the present invention is that the surface modified layer 45 is made of a-C:H, F and is doped with NLA group elements, and that the flow rate ratio of fluorocarbon and hydrocarbon is appropriately selected during creation. The composition is controlled.

This improves the mechanical strength and image deletion characteristics of the surface modified layer 45.

If the (H) and (F) concentrations in the film are too high, the scratch resistance will be poor.

Another noteworthy point of this photoreceptor is that in the glow discharge method described below, for example, (B zHa) / (CH4) + (
eF4)・lO−! ~10' capacity pp (preferably 1
The surface modification layer 45 is doped with Group 1 Ia elements of the periodic table with O-1 to 10" capacity pp■). By containing these impurity elements, image blurring can be significantly reduced. In other words, the amount of impurity element is 10-'
When the capacitance is less than ppm or exceeds 10' ppm, sufficient surface resistance cannot be obtained, and image blurring occurs significantly.

Note that the surface modified layer 45 may be made of a Group Va element of the periodic table, for example, phosphorus.

The thickness of the surface modified layer 45 is 200 to 30,000 mm.
It is desirable to make it 1.000 to 1 mouth, 00OA
It is even more desirable that If the film thickness is too large, the residual potential V becomes too high and the photosensitivity decreases, resulting in a-3
It is easy to lose the good characteristics as an i-type photoreceptor.

Furthermore, if the film thickness is too small, charges will no longer be charged on the surface due to the tunnel effect, resulting in increased dark decay and reduction in photosensitivity.

The photoconductive layer 43 as a photosensitive layer may be composed of a-5t:H, and its composition is such that H is 5 to 4Qato■
When a halogen is contained in place of or in combination with H, the halogen is preferably 5 to 40 atom%, or the total amount of H and halogen is preferably 5 to 40 atom%. This photoconductive layer 43 is preferably doped with an impurity, particularly an element of Group 1 Na or Va of the periodic table, in order to improve charging ability. For example, during glow discharge (described later), (BxH
s) / (S i H4) -1O-! ~100 (preferably io-''~10) Capacity ppm, (PHs)/
(S i H4) -10-3~100 (JfF or L
<c10-”-10) Capacity ppl may be used.

Further, the thickness of this layer 43 is preferably 5 to 100 μm, preferably 10 to 30 μm. If the thickness of the photoconductive layer 43 is too small, a sufficient charging potential cannot be obtained, and if it is too large, the residual potential increases, which is disadvantageous in practice.

Further, in order to sufficiently prevent electron injection from the substrate 41 and to improve sensitivity and charging ability, the charge blocking layer 44 is doped with an element of group NLA of the periodic table (for example, boron) by glow discharge decomposition. , Pff (further, P+ type).

It is desirable to control the doping amount as follows depending on the composition of the blocking layer.

(1) a-8i:H (N content 5-40 atom%):
(B2H2) / (S i H4) -10-3-1
0'capacity ppm (even 10-'-10''capacity ppm)
CP H3) / (S i H,) =lQ-”~1
0' capacity ppI11 (furthermore 10-1~lO2 capacity pp
m) (2) a-3iC:H (N content 5-50a
tom%, C content 5 to 1100ato%): (82H@) / (S i Ha) -10-"10
'Capacity ppm (furthermore, 10-'-10' capacity is 9m)C
P )Is) / (S i H4) -10-3~1
0' capacity ppm (further lO-1 to lO1 capacity pp+*
) (3) a-9iN:H (N content 5-50ato
a+%, N content 5 to 60 atom%): (BzHs) / (S i H4) "10-3 to 1
0'capacity ppm (even 10-' to 10'capacity ppm
) (PHs) / (S i Ha) ~10-”1
0'capacity ppm (even 10-' to 10'capacity ppm
) Also, the blocking layer 44 has a film thickness of 100 to 2 μm.
Good. If the thickness is too small, the blocking effect will be weak,
Moreover, if it is too large, the charge transport ability tends to deteriorate. Note that each of the above layers needs to contain hydrogen.

In particular, the hydrogen content in the photoconductive layer (charge generation layer) 43 is necessary to compensate for dangling bonds and improve photoconductivity and charge retention.

In addition to boron, the impurities to be doped include A
Group Ia elements of the periodic table such as ff, Ga11n, TQ, etc. can be used, and in addition to phosphorus, As.

Group Va elements of the periodic table, such as sb, can be used.

Next, a method for manufacturing the above-mentioned photoreceptor (for example, drum-shaped) and an apparatus therefor (glow discharge apparatus) will be explained with reference to FIG.

A drum-shaped base 41 is vertically rotatably set in a vacuum chamber 52 of this device 51, and a heater 55 can heat the substrate 41 from the inside to a predetermined temperature. A cylindrical high frequency electrode 57 with a gas outlet 53 is disposed around and facing the substrate 41, and a glow discharge is generated between the electrode 57 and the substrate 41 by a high frequency power source 56. In addition, 62 in the figure is a source of SiH or a gaseous silicon compound,
63 is a supply source of hydrocarbon gas such as CH4, 64 is a supply source of nitrogen compound gas such as N2, and 65 is 0! 66 is a carrier gas supply source such as Ar;
7 is an impurity gas (for example, BzHs) supply source, and 68 is each flow meter.

In this glow discharge device, first, the surface of a support, for example, an A2 substrate 41, is cleaned, and then placed in a vacuum chamber 52, and the gas pressure in the vacuum chamber 52 is adjusted to 10-' Torr, and the air is evacuated. At the same time, the substrate 41 is heated and maintained at a predetermined temperature, particularly 100 to 350°C (preferably 150 to 300°C). Next, using high purity inert gas or Hl as a carrier gas, SiH or gaseous silicon compound, CHN2, NH3, CO2,0! Vacuum #1 as appropriate.
52, and a high frequency voltage (for example, 13 Torr) is applied by a high frequency power supply 56 under a reaction pressure of, for example, 0.01 to 10 Torr.
56 M tlz). As a result, each of the above reaction gases is decomposed by glow discharge between the electrode 57 and the substrate 41, and a-8i:H, a-5t:Hla-5(CN:
H is deposited as layers 44, 43, 45 as described above on the substrate successively (i.e. corresponding to the example of FIG. 1, for example).

In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-5i layer on the support, so the film quality (especially electrical properties) of the photoreceptor can be improved. .

In addition, when forming the above a-5i photoreceptor photosensitive layer,
In order to compensate for dangling bonds, it is necessary to use halogens such as fluorine instead of H, or in combination with H.
F, etc., a-3i:F, a-Si:
H, Fs a-5iN:F.

a-3iN:) i, F, a-5iC: Fl a-3iC
:H, F, etc. can also be used.

(Example) Hereinafter, the present invention will be described with reference to specific examples.

An electrophotographic photoreceptor having the structure shown in FIG. 1 was prepared on a drum-shaped Ai2 support by a glow discharge decomposition method.

That is, first, after cleaning the surface of a support, for example, a drum-shaped All-in-all substrate 41 with a smooth surface, it is placed in a vacuum chamber 52 in FIG. 2, and the gas pressure in the vacuum chamber 52 is set to 10-
'Torr' and exhaust the air, and the base 4
1 is heated and maintained at a predetermined temperature, particularly 100-350'0 (preferably 150-300°C). Next, high-purity Ar gas is introduced as a carrier gas, and Q, 5 Tor
A high frequency power with a frequency of 13.56 MHz was applied under a back pressure of r, and a preliminary discharge was performed for 10 minutes. Then,
A reaction gas consisting of SiH, B, and H was introduced, and (Ar:
S iH,:BzHs) By glow discharge decomposition of mixed gas, P+ type which has charge blocking function is generated.
a-3i: The H layer 44 was formed to a predetermined thickness at a deposition rate of 6 μm/hr. Subsequently, the flow rate ratio 1 : l : (5
XIG-') of (A r : S i H4: B2H
2) The mixed gas was subjected to discharge decomposition to form a boron-doped A-5i:8 layer 43 of a predetermined thickness. Subsequently, the flow rate ratio 4
0: 3: 90:1.5X 10-'(A r
: S i Ha: C) Ia: BzHs) Mixed gas at reaction pressure P = 0.5 Torr, discharge power Rf-
Glow discharge decomposition was performed at 400 W to form an intermediate layer of a predetermined thickness.

The a-C:H,F surface-modified layer 45 according to the present invention was formed on the intermediate layer with a thickness of 0.2 μm having the composition shown in Table 2 based on the raw material gas inflow and reaction conditions listed in Table 1. Comparative photoreceptor samples and inventive example photoreceptor samples 1 to 1
1 was prepared and subjected to the following evaluation test. Table 2 shows the results.
Also listed in

Note that the composition of the layer was analyzed by SIMS.

Forced jam test Using a modified electrophotographic copying machine U-Bix 2500 (manufactured by Konica Corporation), a jam test was conducted in the following steps.

■Separation current is set to zero and a jam is forcibly generated.

0 Leave the machine running for 30 seconds with no paper jam.

Repeat ■■ and ■ 30 times.

Determine the presence or absence of jam damage by displaying 0 images.

O No jam damage After idling for one hour without contacting the developer, paper, or blade, an image was produced, and the degree of image deletion was determined based on the following criteria.

O: There is no image blurring at all, and the reproducibility of 5.5-point alphabetic characters and thin lines is good.

x: 5.5 point letters are crushed and difficult to read.

Table 1 And, Figure 1 is a cross-sectional view of the a-3t system ill-sensitivity photo, FIG. 2 is a schematic cross-sectional view of the glow discharge device.

39・・・・・・A-5i type bad sensitivity 41・・・・
...Support (substrate) 43...Photoconductivity 44...Charge blocking layer 45...
......As is clear from the surface modified layer surface, proper doping of Ma group elements improves image blurring and suppresses the hydrogen and fluorine content in the surface modified layer within the range of 5 to 55 atom%. This makes it possible to achieve good scratch resistance.

Further, by using a mixed gas of hydrocarbon and fluorocarbon, it becomes possible to freely change the composition of the amorphous carbon film, and it becomes possible to control the composition.

[Brief explanation of the drawing]

Claims (2)

[Claims] (1) Surface modification made of hydrogenated-fluorinated amorphous carbon doped with at least one group IIIa element on a photoconductive layer made of at least hydrogenated and/or fluorinated amorphous silicon. In the electrophotographic photoreceptor having a layer, the content of hydrogen and fluorine in the surface modification layer is 5 to 40 atom%, and the content of fluorine is 1
-30 atom% amorphous silicon photoreceptor. (2) The amorphous silicon photoreceptor according to claim 1, wherein the surface modification layer is provided by a plasma CVD method using a mixed gas of hydrocarbon and fluorocarbon.